Determine the size of your foundation based on your dimensioned sketch. Did you remember to include the thickness of the walls? Assume that all walls will be 6" thick.
Make a scale drawing of your house using 1/4"= 1' scale or 1/8" = 1' scale. Ask your instructor for 1/4" graph paper.
If your house is large you may have to reduce the scale to 1/4"= 2' or 1/4" = 4'.