Assign random lanes but allow choice of time for competition signup form


I would like to set up a form for competition signups and I don’t see how to do it (I’m an airtable newbie, please be gentle).

These competitions are set up in multiple days, with different hours for the competitions and each competitor has a different lane.

The competitor registering should be able to choose the disciplines in which to participate and the time slots for those disciplines, but the lane should be random. Each discipline has a different number of lanes.

He/she should be able to see what has been assigned and who’s competing in the different lanes and disciplines.

How can I do this?

Thanks for the pointers and help!