Thank you for the input! Is this done by a contractor or can you do it yourself with rented tools? If anyone out there has done this, can you tell us about your experience?
We have done this many times. What we do is hire out the concrete portion to a properly experienced "concrete-cutting" company. If you agree to break up and dispose of the left-over concrete, the costs will be less.
1.) Pull building permit. You will have to detail the plan, and the new opening's framing.
2.) Get pricing from concrete-cutting companies.
3.) Get prices from reputable companies to do the framing and window installation - or - do your research and do the work yourself.
Essentially, the work would involve temporarily supporting the first floor joists, above the area, prior to the cutting of the concrete.
The concrete would be cut all the way up to the first floor wall plates. The opening would then be framed out using Pressure Treated Lumber and either tapcons, or powder actuated fasteners. The opening would be spanned by a proper header arrangement, and supported by at least double jack studs, and a king stud.
That is a basic layout. There are more details involved.
I would strongly suggest that you subcontract out the cutting, and the structural framing
. You should be able to take over from there: window install, trimming out, insulation, sheetrock, etc...