Browse the Collab Market to find a like-minded Music Maker to collaborate with. Choose the track you want to use and promote in your post(s) and send the Music Maker a collab proposal. When you reach an agreement, you can download the track in WAV and use it in the agreed post(s). As part of your collab, you obtain a license to use the agreed track in your social media post in exchange for promoting it and increasing its exposure.