I had to go look at the video to see what kind of star they created. They used HST's to form the star points. If your center block finishes at 6 inches, you want your HST's to finish at 3 inches.
If you are making them 2 at a time, you need four bright and four background squares measuring 4 inches. Then you draw your diagonal line, stitch on both sides, cut apart, press gently and trim to 3 1/2 inches square.
If you want to use the 'easy eight' method, you will need two squares measuring 7 3/4 inches. Here is a link to this method.
http://www.blossomheartquilts.com/20...ght-at-a-time/
And a YouTube for the same method
https://www.youtube.com/watch?v=ag0xfRpe_UM
And here is a link to testing a new block without fabric. I hate to waste fabric so love this little hack.
http://quiltingdigest.com/how-to-mak...asting-fabric/