Lay out all your pieces next to your machine. Remember the small squares can be arranged according to your choice...the darker color going into the center of the block or going in the same direction in each finished 4 inch square.
Assemble the small squares together...pretty simple.
Pin one small triangle onto the large triangle. Put the pins through the points you marked on both fabric pieces. The fabric itself will not line up on the ends. Start your sewing on the point that will end up in the center of the 12 inch block if you can. Ease your needle down right on top of the points, remove the pin, put your presser foot down, sew forward a couple stitches, and then back stitch a couple...be careful not to go past the point marked. Continue sewing forward to the next point marked. Remember it's OK on the ends that will be on the outside of the block to sew past the point, but not in the center of the block. Press this open.
Next pin down the second small triangle, also right on the points marked. Sew as the first small triangle was sewn on. You can use the feel of the fabric, the bump of the seam underneath to help you gauge where to stop at the point as well as where the mark is on the fabric. Occasionally they might be a mm off...it's more important to match up the point where the fabric meets than the point mark, but they should be rather close.
When you are done sewing press this open and trim the fabric tags off...the longer pointy ends first like I showed you in class, then square the block on the sides trimming any other excess off.
Lay out all your pieces next to your machine. Remember the small squares can be arranged according to your choice...the darker color going into the center of the block or going in the same direction in each finished 4 inch square. 
Assemble the small squares together...pretty simple. 
Pin one small triangle onto the large triangle. Put the pins through the points you marked on both fabric pieces. The fabric itself will not line up on the ends. Start your sewing on the point that will end up in the center of the 12 inch block if you can. Ease your needle down right on top of the points, remove the pin, put your presser foot down, sew forward a couple stitches, and then back stitch a couple...be careful not to go past the point marked. Continue sewing forward to the next point marked. Remember it's OK on the ends that will be on the outside of the block to sew past the point, but not in the center of the block. Press this open.
Next pin down the second small triangle, also right on the points marked. Sew as the first small triangle was sewn on. You can use the feel of the fabric, the bump of the seam underneath to help you gauge where to stop at the point as well as where the mark is on the fabric. Occasionally they might be a mm off...it's more important to match up the point where the fabric meets than the point mark, but they should be rather close. 
When you are done sewing press this open and trim the fabric tags off...the longer pointy ends first like I showed you in class, then square the block on the sides trimming any other excess off. 
