Hey I actually just bought your rhythm template on GDev, I also bought it on itch.io LMAO but it's fine it's a great template! 
I had a question I saw that there was supposed to be a tutorial with the product on how to set up a level, and also how to map the keys. Are you able to link me where I can find that information please :D 

Hey!

I'm so sorry for the late response! Itch flagged your topic and it didn't notify me, so I didn't realize it was here until today!

"I had a question I saw that there was supposed to be a tutorial with the product on how to set up a level" That tutorial is located directly in the event sheet. If you need any more information about it though, feel free to reply here and I'll respond the best I can.

"and also how to map the keys" For this, open the Arrow Logic event group and look for the conditions that say "Up Key is pressed" "Down key is pressed" etc. If you want to completely swap the key, simply change it there. If you want to allow the up key and another key, simply add the "or" condition, drag the "Up Key is pressed" into there, and duplicate it. Then, change the second condition from "Up Key is Pressed" to whatever other key you want. You can keep duplicating it and adding keys for whichever keys you want to link to that arrow.

Again, so sorry for the late response. If there is anything else you need, feel free to let me know. Also, when your game is finished (as long as it is SFW) you can post about it in the "Showcase" section of my forum.

Thanks! :D