Did you download a sticker pack and it isn’t showing up anywhere? Looks like it didn’t install?
Sticker packs are an iMessage App, so they work inside iMessages not as their own app. That means there is an extra step to activate it inside iMessage before it shows up. So if you just install it, it looks like it doesn’t work.
Sorry! I know that’s super confusing. I wish Apple made this more clear.
Here is a tutorial that can help! Look at the section that says “Manually add or remove apps that you download”. If you follow this extra step, your stickers will work.