What does HDC 2 mean?
So the [HDC 2 times, HDC] means to HDC 2 times in one stitch, then move to the next ST and HDC in that ST. The 8 times after the bracket lets you know you will repeat those stitches 8 times around. So HDC 2 times in one ST and then HDC in the next.
What does HDC INC mean?
Hdc-inc means half-double-crochet-increase. Unless there is a specific special stitch instruction, the basic increase method is to do 2 of the same stitch into the same space.