Here is an in-depth video on how to do the basic brioche stitch.
Brioche stitch is a two-layered fabric that looks somewhat like ribbing, although it is constructed differently.
Like ribbing, it is reversible and can be used to make all types of garments, with cables, increases, decreases, and color-patterns.
Like double-knitting, brioche has two right-sides, but unlike double-knitting, the two sides are knitted one after the other, instead of all in the same row.
Brioche stitch can be done with one, two, or as many as five or six colors, and incorporate Intarsia color-blocks, just like regular knitting.