3 current event 93/94 + 2 any 93/94. Cards need to be out of your lineups to use in a set.
You can do the following to work towards 96s: free daily store pack that gives 5 free event collects, wildcard offers collects, event objectives which offers a 93 event ovr and collects. totw objectives which offers a 93 ovr. moments (event, tots and weekly) also has some additional cards. You can also use 89s/90s to build event 93s. 3 89s/90s = 1 event 91, and 3 event 91s = 1 event 93.
30 event collects can also be exchanged for a 93 event UT. Do not redeem for the BND as those are account bound and cannot be used in sets. Wildcard and Moments also offer an event card to use towards objectives. Cup Chase on rookie is the fastest way to complete objectives.