Pins 30 through 38 (ROW and COL pins) map to the corresponding Keypad Row (PC[x]) and Keypad Column (PA[x]) from the ADSmartIO manual. For example J31:30 is marked as ROW0, which corresponds to ADSmartIO port PC7.
When looking at the I/Os on the Bitsy, be aware of the pinout changes between board revisions B and C outlined in the errata here.