I like to grill fish as one piece. In other words, if you are making a recipe for 2 as is the case here, grill fish as one and portion before plating.
Begin by marinading the salmon by making cross slits on on the salmon about 1/4” deep as seen here. This creates lots of places for the marinade to hang out before and during grilling.
Rub chopped garlic and EVOO into the slits and all around. Let marinate from a few minutes to preferably 1 hour.