So here it goes:
for small bag
10.5 by 8.5 2 each of lining and main fabric
6 by 4.5 1 of lining and 1 of main for flap
14.5 by 12.5 2 each of lining and main
8.5 by 5.5 1 of lining 1 of main for flap
then use those pieces to cut out interfacing and insulate. don't forget to cut out handles if you are doing cloth handles, for the sample I used 1 inch belting.
first, take your ruler to the bottom corners and cut out 2 inch squares (2.5 for the large bag) at both sides.
then use the ruler to make a 45 degree angle on the flap, do both sides. make sure the flap is wider than it is longer! If you don't want to do this way, you can take a quarter and round the edges.
Here are your pieces so far. Iron on the interfacing to the MAIN fabric.
Then with quilt basting spray, you are going to attach the insulate to the lining.
like so. Trim so that there is no overhang from the insulate or interfacing.
center a 1 inch strip of sew in velcro about an inch or so from the edge. sew down. Pin and sew with right sides together the flap
Then you can topstich 1/8th inch around. the edge. Topstiching just makes everything look better.
take the other piece of velcro at the top edge of the front piece of main fabric and center it about an inch or so down, on the big bag I did about 2 inches.
sew the sides and bottom of the lining and main pieces
box your corners.
attach flap. I fold the flap in half finding center, then find center in the back of the bag, pin and sew. Sew at 1/8 inch, so when you sew the bag together you don't see that seam.
choose your handle length. I did short ones. Pin to main fabric, centering with the seam. Leave about an inch over, to reenforce. sew at 1/8th inch.
Place the main fabric into the lining so right sides are together. pin carefully, especially at seams. Sew around, leaving at least a 4 inch opening in the fron to turn. Turn right side out.
Carefully topstich at 1/8th inch, closing the opening.
reenforce your handles. Trip your threads and you're done!