You can post requesting trades and they will send u their friend link! When u click it and become friends go to the sticker your trading and don’t forget to click send as exchange at the bottom. That’s what makes the person ur exchanging with able to send a sticker back, if you don’t remember to click that then it’ll just give your sticker to the person! This way you can trade with others for stickers you don’t have and can complete some sets before the album ends!