How is BLM?

[Brandedblade]

The biggest part that confuses me is Fire 1. It's like, why do we stick that in when we have access to F3 & F4?

Fire 3 and Blizzard 3 are incredibly cheap (free once you get to level 72) and fast casting, but only when you're in the opposite element phase. Casting them in the same element phase makes them slow and expensive. So the purpose of Fire 3 and Blizzard 3 is to quickly switch your stacks over when you're done with your element phase.

Tl;dr:
Fire 3: Use to switch to fire while in ice phase, or to move/deal damage with a Firestarter proc
Blizzard 3: Use to switch to ice while in fire phase.
Fire: Use to refresh your fire stacks while in fire phase.
Fire 4: Deals the most damage but doesn't refresh your fire stacks.