94 camry Cd player installation

Hey guys im new to these forums but i have a question my gf has a 94 camry and i am putting a cd player in it removing the stock one. and i heard they didnt make a wire harness for that year and that you had to wire it to the stock amp underneth the seat??? or do i wire it up just like i would on any other car? any help would be greatly appreciated thanks

If it needs to be wired to the amp could someone briefly explain to me how it is done? thanks