I want my plugin to add the command /secretshop that opens up a menu with the size of 27 slots and you can buy a mace by clicking on slot 13 and i want a mace to be on slot 13 too on slot 10 and 16 I want there to be barriers saying "Unreleased" and when you buy the mace I want it to make a sound and broadcast a message to the whole server and I want it to give you a Mace named "Mace of the Universe" in red with 10 lines of lore and I want it to have flags to make the attributes hidden and i also want the menu to have black stained glass to act like filler items to make the menu more smoother and my server is running on 1.21.11