Hi there! If one of the substituents in a benzene is methane, this will be considered as a benzene derivative called toluene, so that methyl will be considered as locant 1. Then proceed to the rule for the substituents where we must give the lowest possible locants. Check out the Nomenclature of Benzene Derivatives here: https://www.clutchprep.com/organic-chemistry/benzene-nomenclature/?c_id=14902
Hope that makes sense!