please i i dont know how 8-[

Go to your inventory, click the text that says "switch to equipment"
Using the dropdowns, select the pet you want to equip (left dropdown to select stable, right to select a pet in that stable)
Once it swaps the pet preview to that pet, click the two pieces of equipment you want to swap (or an empty space and the equip, if you're either entirely removing an equip or filling an equip slot the pet doesn't have filled)- when one is selected, it'll highlight green, when the second is selected, they'll swap

(note: equips must be in the right slot on the pet- if you, say, select a bracer and click the armor slot it'll tell you with a popup that that isn't the correct slot)
(note 2: make sure the equips you're putting on a pet are the right sort for that pet! (and also not an uncommon equip because uncommon equips are Awful tier))
(note 3: you cannot change a pet's equips if it's on a mission)

ok ^_^ !! ty /gen