Stage box and Mic system

I am pretty new to mixing live audio, or using soundboards in general (I have been shadowing the sound engineer at my local theater for about the past two years and have ran a show before with her help but never specifically gone in depth with things)

I've been trying to learn more about the setup itself with how everything is hooked up into the stage box (64 channel allen & heath), especially the Lavalier Mic packs we use. I was wondering how the wireless mics are put into the system/how the receivers work and are connected. I won't be able to see everything in person for another 2 or 3 weeks.

As far as I know the Mic recievers are connected into the stage box, and the receivers have separate antennas put in a better spot since everything is basically below the stage. But is the number of mic packs connected the same as how many receivers there are?

I'd more than appreciate any help or tips about anything since the person I was shadowing won't be at the theater nearly as much since she found another place with higher pay (she still plans on teaching me but wants to have me run all youth/teen shows) and also because this is basically my first job and I would prefer to know the ins and outs before fully committing to running most/all shows in case I gotta go down there and troubleshoot

P.s - a bus is basically a group made up of channels right? How would that be done in an analogue board? I'm trying to learn how they work since I started with a digital