Tom
I have a Multitec with Autocom fitted.
It is so easy to do, much simpler than an Arai.
(1) If you have it fitted, take the draught collar off. It makes it easier. You can re-fit it afterwards.
(2) The speakers go into the cut-outs, where your ears are. You can see them at the top of the buckle straps. You may have to take the cheek pads out. I don't think I did, either way, these are easy to take out, too. Hold the speakers in with velcro.
(3) The wire of the loom slips in under the rear of the neck padding. You can hold it in with little bits of gaffer tape, but I didn't bother.
(4) The lead for the Autocom wire exits on the left of the helmet. If you hold the helmet upside down, chin pointing at 6 o'clock, so that you are looking at the bottom of the helmet, the wire exits at about 10 or 11 o'clock.
There is not a lot to take a picture of, to be honest.
Take the wire loom, attached to the speakers and simply hold it up against the inside of the helmet. It becomes obvious what you need to do.