You have learned the simple, yet potent brand of spellcasting for which Warmages are known.
Cantrips
You know four Warmage cantrips of your choice. Force Dart, Prestidigitation, Quickstep, and Shocking Grasp are recommended. Whenever you gain a Warmage level, you can replace one of your cantrips from this feature with another Warmage cantrip of your choice. You can't replace a cantrip that is a prerequisite for a Warmage trick, unless you replace the trick at the same time.
You learn additional Warmage cantrips of your choice at higher levels, as shown in the Cantrips column of the Warmage Features table.
If another Warmage feature gives you cantrips, those cantrips don't count against your number of cantrips known, but otherwise count as Warmage cantrips for you.
Spellcasting Ability
Intelligence is your spellcasting ability for your Warmage spells.
Spellcasting Focus
You can use an Arcane Focus as a Spellcasting Focus for your Warmage spells.