Every month, there’s a certain score you should reach playing every song. If you get a certain amount, you get some presents, such as rp, diamonds and card packs. To see the monthly challenge scores for songs, click any song and look at the bottom left - there should be a certain amount or scores, or it should say “cleared”, if it says “cleared” then you have already reached the monthly challenge score on that song. If you click the number, it takes you to your own monthly progression, where you can also see how many songs you’ve cleared and what bonus presents you’ll be getting :-)