To upload and use Discord Sticker Packs you need to have
Discord Nitro and a server with at least 1 boost level. To upload and use the
Memeful sticker pack you need to extract the zip file on your desktop, then go to the "server settings" page, under the tab called "stickers" you should see an option to upload a sticker. You should click the round plus button then select ane image from the pack you just downloaded from this website.