have a deadline for the league to post their keepers from last season. of course, they'd need to go to last year's team for this and then you'd need to verify it.
go to commish tools and down near the bottom you can finalize your league where keepers can be put in by the commish. when the draft starts, the keepers will go off the board as the 1st rd pick for everyone. it's easier this way. other ways manually just screw up...someone always makes a mess of their pick. gl!