I need to enclose this porch. What are the things that I can expect to have to do?
Aside from local code, building the walls with proper header(s) for door(s)/window(s), electrical outlets and switches, you are on the right path. Big issue I see is the concrete slab. That will be a heat loss issue. You could potentially build it up with some insulation inside the cavity, but you might be limited in height to have it the same as the current room floor.