Taken from the link posted earlier

Method 2 – Squares

This is the simplest method for creating the DinS component. You use only squares, so there’s no bias edge to worry about, and the measurements are pretty easy to calculate. It’s greatest drawback is that it wastes some fabric, but, as with the Flying Geese unit, you have the option of sewing a second seam and saving the HSTs created with the waste.

Measurements are based on your finished block size (not including seam allowances). Start with your center fabric. Cut a square that is 1/2″ larger than your finished block size. For example, if your finished block will be 6″, cut the center square at 6 1/2″.

Next cut four squares for the corners. The squares should measure half the finished block size plus 1/2″. So if you finished block is 6″, your squares should be cut at 3 1/2″ (half of 6 is 3, plus 1/2″ is 3 1/2″).

Draw a diagonal line from corner to corner on the wrong side of each of the small squares. If you use a seam guide on you machine, you may not need to draw the lines – just line up the point with the needle line and sew, keeping the point on the seam guide line.

If you want to reclaim your waste fabric, sew a second line 1/2″ outside first line. (Draw this line, too.) With smaller blocks you often don’t have enough excess fabric in the corners to create HSTs. Sew the squares onto opposite corners first.

Trim the excess fabric, saving the HSTs if you sewed the second seam.

Press the triangles (pressing to the side or open makes little different when assembling these into blocks, so do whichever you prefer). Sew the next two squares in the same manner.

Trim the corners off, again saving the HSTs if you sewed the extra seams.

Press, and you have a Diamond in a Square!