I am trying to make it so that the accounts can log in, but they keep showing an incorrect user/password. To prevent this, I wanted to try assigning a row in a spreadsheet to one thread. Is this possible?
Export your spreadsheet as csv file, than import it to BAS as a resource and set it to use each line 1 time (it is default setting I think). That way each thread would take new line from your csv file in run mode or as compiled bot.
If your cookies in same format as BAS, you just read it from file to variable and go Network-load cookies-set cookies for browser. If format of your cookies not compatible with BAS, compare and convert all your cookies in right format