how can the ALLEN&HEATH_GL2200-412 mixer be connected using a system

With Cables
Fuckwit! 

The majority of inputs on the desk will be XLR or TRS Jack plugs.

Mic inpouts will be XLR and the line level inputs will be TRS.

This will be common on most desks this size.

I hope this helps.

SafeandSound Mastering

online mastering
 

[Edited: 23-Mar-11  |  05:48 PM]