Underlaps and Overlaps in wingerless formation

[Corperate]

Hello all,

I have noticed that the standard vertical tikitaka set up with 532 formation uses underlaps team instruction. In this instance is the player who is looking for the underlap = the wingback?. I.E The wingbacks look for a midfielder or striker to make a run inside them, not crossing but instead playing an angled through ball? This is my current understanding but have seen in other forums different things posted.

Also in relation to this does the Overlap instruction again in wingerless formation ask the wingbacks to overlap the midfield or striker: or the wingbacks are looking for the overlap from the center backs

One last question would be what is the difference between exploiting neither the middle or the flanks... Or instead middle and overlap....   Tempo and counterattacking style?

I would be grateful if anyone where to help with this.

Thanks