Installing sliding windows in alu walls

Hello everyone. We are installing alu sliding windows into our truck. Walls are made of riveted alu sheeting with steel braces and we want to avoid putting holes into the exterior alu sheets as much as possible.

Does anyone have any suggestions on how to install these windows? Is the window frame profile useful in any way that we are unaware of? Any advice is very welcome :slight_smile:

What sealant should we be using to seal the outer edge of the window to the outside of the truck?

another photo