Is it acoustic, classical or eletric guitar?
1. Check the basics lesson on youtube.
( Placing your fingering hand, placing your picking hand, holding thr pick, strumming, alternate picking, etc )
2. Learn how to read tabs ( mostly for electric guitar ) / chords ( mostly for acoustic guitar )
3. Head over to ultimate-guitar.com and learn the songs you like!
If it's electric guitar, I could probably give you a few hints if you wish.