Here is a design I was playing with when trying to get a nice vent out the window. I figured it was a good 2nd project to try and learn on.
In the file you can see the A circle is larger as it is the base circle on the window cutout. Then you stack and glue the B circles on top. You also place the TOP/BOTTOM slides for guide rails to hold the newly mounted holder in place.
I think the template I was using for Illustrator was a bit too large as it didn’t allow me to cut it all on one sheet (despite fitting in the template). Hopefully it works for you by moving items on and off the cutting view to get it all cut.