Joe, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy this website and forums.
First you will need a helper and means to comfortably get the window frame off the coach and the new one back on. They are heavy and so a strong ladder or scaffold is necessary. You will begin by cutting the sealant if any, on Winnebago, there may not be any that is visible. One person will remove all of the screws on the inside window trim ring and the other can stand watch on the outside. With the Winnebago it is not likely the window will fall out. As a matter of fact, it will be a job to cut, pry and pull the old window frame off but it will come off. After it is out, clean up the wall the window came out of and install butyl tape to the frame of new window. Reverse the removal steps and trim off the excess butyl putty. After a few days you can trim off more excess. Then clean the surfaces and seal the top and two sides with a clear silicone or better yet a product called Pro-Flex. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7