Set up the equipment at the DJ booth before the show starts. Configure the equipment the way you like it; this usually means the mixer in the middle and the turntables on either side.
Plug the turntables and headphones into the mixer.
Plug an audio cable into the amplifier/receiver.
Turn on the equipment with the volume down.
Start playing a track on one of the turntables and slowly turn up the volume until it is audible.
Test both turntables and make sure that all the equipment is working correctly. Do a short mix as a dry run of what will happen at the rave.
Tweak the equalizer on the mixer for the best settings for techno. This usually means increasing the highs and lows and leaving the middles untouched. However, this depends on the acoustics of the venue and the music you play.