Tokøta from Mastering.com breaks down the fundamental difference between audio and MIDI tracks in Logic Pro. Audio is sound from the moment it's recorded. MIDI is just note data telling a software instrument what to play, with no sound of its own until an instrument renders it.
Once that distinction clicks, the signal flow is identical for both. Input leads to processing (EQ, compression, distortion), then down to the fader, panning, and out to the stereo bus.
Sends get introduced as a way to route a copy of the signal to a separate channel, like blending in a reverb, without altering the original track. Understanding this order is what lets you make deliberate decisions about where in the chain each processor should sit.