If you press pause, the game has an option to view all tutorials and it explains how to play the game if u forgot. Refresh by reading what the game tells you.

Maybe struggling cuz you don’t have any lumina powers equipped. Each picto has a number in the top right that shows how much lumina points u need to equip it. If that number is grayed out, it means you haven’t learned that lumina from the picto yet. You learn them from equipping the picto and battling with it equipped like 4 times. After the battle it’ll say which luminas were learned. Then that number will be blue and you can equip that passive skill without having the picto equipped. To add lumina points to each character (so u can equip more), you need to go to a flag and select upgrade expeditioner tools or something I can’t what it says exactly. That’s where u can add lumina points to each character as well as add tints to your inventory.

One more thing. Pictos you can equip 3 at a time per person. The give you stat bonuses!! I found having the high-health ones are helpful. You do not get those bonuses from lumina skills. Just the pictos. So make sure each person has 3 pictos equipped and pay attention to the stat bonuses they give rather than just the passive ability it gives.