Baby I'm Gonna Leave You By Led Zeppelin
You Can Do It Fingerpicking Or Economy Picking
It's, In MY Own Opinion, the Decider, If You Can Play This Song To The Right Speed then you've Mastered Economy/Fingerpicking

Btw For Beginners Lookign At The Tab, The Trick Is Getting Your fingers Into Chords. would be very sloppy otherwise if you coudl do it at all