musician collaborator

How do you collab and both get credit if a video is on one person's account. If on both how does the algorithm choose who gets posted higher in search? Anyone wish to colab with me a musician? You can use this song.

Okay, I know it's early for Christmas and Sleigh Bells but hear me out! I'm planning a Christmas Project for December, but it's going to take a lot of Co-Ordination and patience and time to sort out and get everything ready - hence why I'm starting in September! I need all kinds of performers...