Sew/Cut is where you do stripes cut to the width you want, sew then together and cut into the size block. This is used for 4 or 9 block patterns.
If you want triangles, you put two fabrics together, then you mark a line on the 45% which will become your cutting line later. On each side of this line, you will mark 1/4 each seam allowance and this will be your sewing line. be sure to add a little to each block as they will get smaller from cutting this way. Now sew on the 1/4 inch mark on each side of the 45 line. Cut on the 45 line and you have your triangle sewed together without sewing an a bias cut. Perfect triangles every time. You can also do a 60 or 90 degree angle by sewing several pieces of fabric together. Then take the 90 degree line on your ruler and cut. I'm sure this is as clear as mud. I think if you will look on line for the Perfect piece triangle, you will find some pictures.
When I applique and their are several leaves or flowers that are the same. I sew 2 of the leaves together using wash away thread in the bobbin, turn, press and mist the thread. Now you have your edges turned under for applique, much faster than trying to turn them by hand.