Core answer: you only have one suit slot until you finish the first main chapter. Do not overthink your starter class or spend resources waiting - clear the chapter, then pair whatever suits you actually have.

1Chapter Walkthrough in Order

When Act 1 Chapter 1 shows complete, the full Suit Room opens. Equip a second suit there - you can now swap in combat.

Key Decision After Unlock

ChoiceWhy
Equip two complementary suitsDifferent ranges or roles work well, e.g. frontline plus AoE. Do not lock into one "best" class yet.
Learn which attacks you can cut shortSwaps reset moves, so knowing what cancels keeps combos going.
Wait for the Perfect Change gaugeSwap when the other suit's gauge is lit to get the extra skill, buffs, and Burst Gauge charge.

Common Mistakes to Avoid

Video Walkthroughs

Beginner guide covering the unlock timing and dual-suit setup
Chapter walkthrough with timestamps for mounts, fights, and the Goliath section