Hi! First post!

I need to add a basement bathroom window onto a SIP  that does not have the rough opening yet, and floor joists sit onto the panel.This is a finished hoese with a unfinished basement.  The window will be approximately 2' wide. On this situation where the floor joists are resting on top of the SIP, what precautions should be taken to cut a rough opening in this pannel? What should be done to the opening to re-inforce the structure of the panel?