creating associative entity tables in mysql

[Kyle Davis]

i have a bunch of associative entities that i need to create into tables.

Lets say I have table 1 and table 2 and the associative entity table 3. Do I just take the names of the primary key fields in tables 1 and 2 and create them in table 3 and then set both to a primary key? Or is there a procedure like when setting a foreign key?? THanks so much