Going to a Chicago Blackhawks home game? Here are 3 things to know, including a new policy banning almost all purses and bags.

The Chicago Blackhawks christen the United Center for the 2021-22 season Tuesday night against the New York Islanders, and for some fans it will be a baptism in relearning the do’s and don’ts of attending Hawks and Bulls home games.

For many fans, Tuesday’s home opener might be their first time entering the building since 21,275 watched the Hawks host the San Jose Sharks on March 11, 2020.

Since that date — a day before the NHL suspended the season because of the COVID-19 pandemic — the Hawks have played two regular-season games at the United Center with fans in attendance, and those were with limited capacity: about 3,900 for each of the last two games of the 2020-21 season, both against the Dallas Stars.

Preseason attendance at the United Center has been robust, with 15,154 showing up for the opener against the Detroit Red Wings on Sept. 29 and more than 16,000 and 17,000 for exhibitions against the St. Louis Blues and Minnesota Wild, respectively.

The arena holds 19,717 for hockey and 20,917 for basketball.

Several new policies have been in place during the summer concert season at the United Center as well as for Hawks and Bulls preseason games.

Fans can find a lot of this season’s changes on the arena’s “Know Before You Go” page, but here are three important details we learned Monday.

1. Midsize to large purses no longer will be allowed.

Backpacks already were banned, and the United Center has added purses to the restricted list.

“We have the no-bag policy. This is a change from even last year and years prior for fans that recall what attending events at the UC used to be,” said Joe Myhra, United Center senior vice president of operations and administration. “This is a change from league protocols that we’re adopting at the United Center for both teams and all United Center events.”

Bags can be no larger than 4-by-6-by-1 inches — about the size of a clutch.

“Really, your phone fits in it with your credit card — that’s about all you can bring,” Lyndsey Stroope, Hawks director of public relations, said during a media preview tour. “There’s no clear (bag) options like some other leagues have allowed.

“Some of our fans have equated bags with backpacks, which have never been allowed, but it is a much more strict requirement now.”

When asked about the reason for the policy change, Myhra said, “We work with both leagues, the NHL and the NBA, (and) there’s a number of concerns — one is safety.”

Myhra mentioned “friction points,” which require stadium employees to come in closer contact with fans and slow the entry process.

Medical and diaper bags are acceptable, and for fans who do bring purses and other bags, there’s a bag check at Parking Lot J at Wood and Monroe streets, adjacent to the Advocate Center.

2. Just a reminder, you need to show proof of vaccination or a negative COVID-19 test.

No surprises here. Team and United Center officials announced last month that all fans 12 and older will be required to show proof of full vaccination (both shots) or a negative COVID-19 PCR or antigen test to gain access to any event at the arena.

A fan can take a picture of his or her vaccination card and show it on a phone as proof.

“It is super simple. Like I do in a lot of places, I have my vaccination card, a photo (of it), on my phone,” Stroop said. “That is totally acceptable, printed or digital proof. If they have CLEAR (the app’s Health Pass digital vaccine card), they can continue to use that, but if it’s easier to have a photo ‘favorited’ on their phone, they can do that too.”

When fans enter, they’ll first show the vaccination card or negative test to a stadium employee. Then they’ll go through a metal detector. Next they’ll scan their ticket on a monitor.

All entry is via mobile ticketing apps — no printouts or even digital screenshots of the ticket. You can use Safetix’s barcode app, while the Ticketmaster app automatically stores an image of the ticket once it’s viewed. Or you can download the ticket to an Apple or Google wallet.

“To avoid connectivity issue when there are lots of people here, we definitely recommend putting it in your digital wallet,” Stroope said.

As part of the safety measures, all concessions are cashless and fans can order food on their phones from their seats.

The United Center also has new state-of-the-art “fresh air flow” to cycle in air every seven minutes.

In keeping with city and state mandates, fans over 2 must wear masks over their noses and mouths at all times “except when actively eating or drinking.”

3. Concessions and food options have a different look.

United Center officials unveiled the new 1800 Market space, like an in-stadium convenience store.

It has a range of snack and drink choices (both common and eclectic), from Goose Island Sox Golden Ale and Takis Fuego chips to L’Appetito salads and Häagen-Dazs ice cream. The store requires a credit card swipe to enter and Amazon’s “Just Walk Out” technology to avoid a cash register (though you can get an email receipt from a kiosk).

The idea sprang from a partnership between the United Center, Levy Restaurants and Amazon.

“We’ve been hearing for years how fans want to control their experience more, they want a faster, easier way to shop. Nobody likes lines, right?” said Kevin O’Brien, the United Center’s director of food and beverage. “So what we’ve seen — we’ve had this open for several games and several concerts over the last couple months — it is an absolute line-buster. Usually under 60 seconds. ... It’s a different mix of food and beverage options that you might not find around the arena. So more variety.”

Fans can order at traditional concession stands in person or through their phones. There are QR codes for menus on stanchions branded with either the Bulls or Blackhawks logo.

“If you’re already in the app for each team, you can click through and find very easily ‘order food and beverage,’ ” O’Brien said during a tour. “Open up your camera, scan the QR code, it will ask if you if you want to open it in the team’s app. ... It will pull you right into the mobile ordering menu. Just a reminder: You always want to order from the section that is nearest to your seat.”

O’Brien said stadium officials project about 20% of fans will use the mobile-ordering feature in the first year and it will grow from there.

There are new dishes sprinkled around various sections of the United Center.

Chicago chef Stephanie Izard’s This Little Goat will be available at Sections 114 and 230. Options include short rib tacos and Nacho Average Nachos, while a big hit during the media tour was the goat empanada.

Section 115 will have Honey Butter Fried Chicken’s OG Chicken Sandwich and fried chicken strips.

Queenie’s, a speakeasy-style lounge and restaurant that’s also open to patrons who aren’t going to the game, has added Amish Chicken Vesuvio, pan-seared scallops and a “Lazy Susan” appetizer tray.

And the United Center is following a popular trend with plant-based offerings: the Field Roast Stadium Dog — a take on the traditional Chicago-style hot dog — and the Legacy Burger with American cheese, lettuce, tomato and secret sauce.