Hi,
From the internet:
Tango uses an aluminum-framed wall construction (not wood stick),
insulated with R7 structural-block foam, then covered with a gel-coated
fiberglass Lamilux 1000 skin that resists denting.
You need to find where the aluminum wall studs are in order to avoid
them... Ideally one of the new window's edges would one of the studs.
Use a Studfinder.
Usually you will need to put some sort of support around the edge of
the new opening you cut. Be careful.... it is not a project to be taken
lightly....
Uncle Larry