Doors and Windows - installing alumin window

I am going to replace our front room window, which is 23"x19", it is like living in a basement, ha. I am going to install a 73"x37" window w/frame. Never have done it before, and would like some suggestions, Do I cut the wall out to the windows size? as there is a 3/4" ear? or edge on the outside of the window, I assume this is for nailing or screwing to the frame area. Any input would be of help, Hiring a contractor is out of the question...Thanx...Joe

The first thing you will have to do is frame the opening for the new window. If you don't how to do that RIGHT, hire a contractor. The few hundred dollars he will charge is a whole lot less than the tens of thousands of dollars of damage you will cause by doing it wrong!