First Trike, I got some questions

[nekroman]

So I picked up this trike, and connected to the seat post it has these supports that have set screws in them, I haven't messed with them, because I don't really know what they're for.

They don't look like they are supporting the seat post, but my assumption is that if you mess with the set screws, they will tweak the back axle, is this correct? If not what the heck are they?
Thanks in advance.

 

[bits n pieces]

If its like mine was. You loosen up the set screws and two lower bolts and it lets you adjust the chain by moving the rear end .

 

[nekroman]

Thanks, like I said, that's what I assumed, but didn't know.
You say like it 'was', does that mean you don't have the trike anymore, or did you change/alter something in the setup?