Each audio track has an "FX" button. These are inserts and are pre fader. The master has "FX" buttons that are also inserts and are pre fader. Each track also has an "AUX SEND" that is post fader. Above the Master faders are the 8 Master AUX busses were the effects are used.
This is standard console convention except that on a real console "AUX SENDS" can ussually be set to either pre or post fader. If your using an "AUXSEND" for monitors it has to be pre fader.
Inserts are typically used for DYNAMIC EFFECTS like compressors were "AUX SENDS" are used for reverb.