am planning to replace two windows (single pane, aluminum frame, window
panels fold sideways out for ventilation)
each new window must pass new requirement for storm force winds but all big
box shops in our area carry these from multiple manufacturers

house is block construction, built circa 1960-1962 and located in the deep
southeast

am hoping someone can give me couple tips on how to proceed on the following

1. it's my understanding that the aluminum metal frame sits in the window
opening but is covered by a small amount of cement/stucco (half inch to one
inch?) all around the frame

2. if I knock out this stucco, the frame should then sit on a wood frame
where it can be unscrewed and disposed of

3. assuming for the moment that my window sizes are available, the
installation steps are roughly the reverse of 2 and 1

4. is it better for purchase from local "window specialist" businesses or
from the big box shops (ie. lowes, home depot)

as I'm sure I'm missing something, would someone please post a couple
comment.
any links to websites with examples or how-to's would also be welcome.