Here's how you start....find some cute fabric and make a pattern the size of your choice. Pin the pattern down and sew around it with a straight stitch, keeping your fabric turned right-sides out.
Next, using wide, single fold bias tape (or you could use double-fold which is easier), pin your bunting flags to the bias tape.
Sew the flags into the bias tape using a small zig zag stitch.
Make your bunting as long as you would like it....mine is a little over 3 yards long (requiring two packages of bias tape).
Here's what it looks like hanging temporarily in my foyer.