I regard this block as a variation of a nine-patch. No, it isn't simply 9 squares of the same fabric, but 4 squares that are made of 2 half square triangles, four squares that are made with half and quarter square units, and one square that is 4 quarter square triangles.
Make each of these 9 components separately. I make the quarter square triangle block just as I would make a 4-patch using squares.
When you have your nine square components made, trim them down to the same size. Arrange in 3 rows of 3, with the half square units at the four corners; the half and quarter combined triangle units along the edges, and the quarter square triangle square in the middle.
Do you have some scraps of mismatched fabric that you could practice on? Are you pretty comfortable making Squares with half-square triangles?