Has anyone installed TNT Customs Sliders before? Question inside

I just picked up a set of never mounted sliders. They came with all of the parts and instructions. I was reading the instructions and I have a question about where they install to the pinch seam. It says in the instructions to use the self tappers to install the flange on the slider. There are no holes on the slider or enough room from the slider side to run a self tapper. So imagine you run the self tapper the other way. But by the looks of it the self tapper will then run through the seam mount into the main square tube. This just seems not right.

If you can confirm this or I am thinking this differently I would appreciate it.

yes some one has installed them before, you are not the first to do it... lol just messing with you...

you have any pics... the ones on the web do not explain much

I got ahold of TNT And yes the self tapping screws do go though the main box tube. I think I am going to pick up a few grade 8 bolts and nuts and use them where I can fit them and self tappers where I cannot. I will take some photos when I mount them up.