If you downloaded a pack for a specific competition, read the terms carefully regarding where you are allowed to post the final track. How to remix a song: A step-by-step guide - Music - MAGIX

To maximize your growth, don't just "remix" the song. Try these exercises:

While there is no official "RemixPacksClub" development guide, many producers use the platform (or similar communities) to find —individual audio tracks like vocals, drums, and bass—to create remixes.