Get at least 1 dressbloom (equipment) before spending pumpkins or anything on manyus.
There are 4 pieces of jewelry to equip, which are:
Ring (lots of ATK)
Earrings (rare, but also some ATK)
Bracelet (Defense)
Necklace (some Defense)
And I'd *really* suggest equiping them on your girls in that order too, so by the time you have dozens of girls, you can quickly see what she has equiped.
ATK is really the more useful stat, you want to stack as much as you can on a girl.
Every girl comes with the first slot unlocked, so if you have a ring (high ATK bonus), you should equip it right away.
The second slot is the first one you have to unlock. Most logical is to put the Earrings (lower ATK bonus) in that slot.
You can always put a Bracelet into the second slot if you don't have earrings available, or need the Def for a particular mission (doubtful, but it's possible). But if there's something your girls could skip for now, it's Defense, so you can postpone the third (bracelet) and especially the fourth (necklace) equipment slot until you're confident that you took care of higher priorities.