You will need header material unless you are running joists the full first and from foundation wall to foundation wall. You could order a full length lentil (sp?) or build one on side. What are the dimensions? 25x25?
You'll need a top plate and sill seal to run the perimeter of the foundation. Usually 2x8 treated.
Then floor joists or engineered I-beams. (You can get these at auction sometimes for peanuts)
Measure the length of your foundation, assuming 25' x 12" divided by 16" x 2 will give you the rough number of 2x10' or 12'. Whatever is code there. Order extra for your rim board.
Then you'll need your subfloor. Length x width divided by 32 will give you the number of 3/4" sheets you'll need.
Sidewalk, length of wall x 12" divided by 16" will give you exterior wall stud. Measure all 4 exterior walls and add 30%. Also order some 12' 2x6's for top and bottom plate. Approx 24 of them for dimensions of 25x25.
Exterior walls heating will be length times width divided by 32 for total sheets of 7/16" osb needed.
Then any interior walls will be the same formula: length of wall x 12" divided by 16".
Roof trusses, go to a lumber yard and order them. Takes the guess work out of it.
5/8 roof sheathing, length of truss times width of truss divided by 32. Make sure you account for soffit overhangs.
This will get you really close to your framing material needed for a project this small.
Don't forget to glue down your subfloor or it will squeak when you walk. --50.107.xxx.xx