This vertical half-screen mixer has four stereo channels with sends and returns and auxiliary input.
Route up to two effects chains from this mixer as sends/returns. Add the desired effect(s) to your table and then use Routing mode to connect the mixer send to the effect(s) and back to the mixer return. A send outputs a variable amount of each channel signal through the effects chain you created. A return controls the amount of affected signal that comes back to the mixer. Changing the send amount on each stereo channel affects how much of the effect is heard on the signal for that channel. Changing the return amount for the given send globally controls the amount of effect heard.
Route another mixer (or line level device) into this input. It is not affected by anything other than this mixer’s Master Level (no effects, no adjustable gain of its own, no pan control).