All GDO flying is on top of guarantee.

So for a 737 FO you will gross $61 per hour * 61 hours for guarantee = $3721 for your base pay.

Lets say you pick up a two day trip on your GDOs. You show at 0700z, or 0200 local, do one leg to MCI for 1:46 of block, and then are released at 1046z for 13:44 of rest. The next day(that night, local) you report at MCI at 0030z, do two legs back to CVG, block 2:08, and are released at 0518z.

Your block has earned you $238, but as the trip was on GDOs you also earn $488 in GDO pay. Which you will see on you end of month paycheck, the following month.