Which bands do you like ?

My advice is, go to a record / music store and get a song book containing songs you A) like and B) know well enough to hum / whistle.

Then sit down with the song book and learn the accompaniment to your favorite songs.

Practice strumming and changing chords.

This is how I started 20+ years ago.

I am in the process of putting together 6 or so "total beginners lessons" which should be finished tomorrow so check the lessons section also !