this is what i want to do:



my confusion lies with the thin wood piece that is supposed to adjust front/back movement. Since this thin piece is secured i can only see it working if there is a mimicked channel underneath it so the bolt can move forward/backwards.

is this correct?

What's difficult to understand?

Loosen the wingnut, slide the lamp/mogul mount forward or backward, and re-tighten the wingnut. It looks like the reflector mount works on the same principal.
The height of the lamp looks adjustable, as well - but it looks like you'd have to take it out to adjust it.

I just wanted to confirm there is a channel underneath on the black part of the box mimicking the slot of the thin white wood used for forward/back movement.

There doesn't really need to be a channel underneath. the bolt could be countersunk into the bottom of the lamp holder allowing it to slide freely.

ok. i follow. this is a better idea. im just concerned using 6mm wood like this builder, there is not much to route out.

The left and right movement slot would have to be routed out underneath the lamp holder right?

The lamp holder doesn't have to deal with a lot of physical strain, so the material size is fine. No routing needed as I see that.

The long channel is supported off of the front and back, bolted to the box. This leaves room underneath the lamp holder for the head of the bolt. (I'd probably use a carriage bolt -- One with a square at the base of the threads, and no hex head or screwdriver fitting -- for this.) There is also a spacer holding up the other part of the lamp holder to keep it level, though this is probably redundant.

Plenty of strength for this application. This gives a lot of adjustment capability, which is a good thing.