Like on the Marshall Mathers LP most of the Dre produced songs list him and Mel-Man on production. For those Mel-Man likely made the beat, with Dre having input on the drums and handling the mix.

Dre would also lead the collaboration with musicians like Mike Elizondo and Tommy Coster who would play live instruments on beats. Dre would handle the recording and mixing of that along with giving them notes on what to play (though Mike Elizondo would often also get writers credit for baselines he came up with.) All of this isn’t to be taken lightly because that mix of live bass/keys along with programmed drums really created a signature sound for that Aftermath era - from 2001 through the work with 50 Cent, Game, etc.