Use a couple music theory tips to find out what key you're in as long as you know a few of the chords. This will work on guitar, piano, violin, anything. Just plug the chords you know into this formula and bam!
To find out how triads are made from a key:
https://www.youtube.com/watch?v=__VtlxQZhXs
To find out how to play the major scale:
https://www.youtube.com/watch?v=KGsmDnn0_cg
iTunes Apple Music: https://itun.es/us/-OyA6
Spotify: https://open.spotify.com/album/3Y8oJWTIPoH1Co1K9QUiv3
Soundcloud: https://soundcloud.com/andres-and-sean
www.seandanielmusic.com