As mana' discusses, this is an MWBC, and the red and black wires are 240V apart. Now...
Do you anticipate needing to power any 240V tools?
If so, the best option is a GFCI breaker back at the main panel.
At this point you're free to wire any combination of common NEMA 5-15 or 240V NEMA 6-15 receps off this circuit (it is ONE circuit).
Otherwise the simplest way is to split the MWBC so each half of it serves a separate 2-socket receptacle, as mana' discusses above. Then you can put a normal GFCI recep on the place of each receptacle.
Sorry to suddenly force you to deep-dive into MWBC arcana when all you wanted to do is slap up a GFCI... but GFCI issues notwithstanding, MWBCs are awesome in garages and workshops. They bring a lot of power (saw AND dust collector) and they can support 240V.