Step 1: Finding the Chords
Once you know how to play the song, you have to press ONE key and see if it sounds right.
If it doesn't, then try another key.
Step 2: Getting the Chords
For me, the right key was 'E' so I add 4, then 3.
So, when I play the chord, I'll press...
E, F# , B
It's a little bit tricky at first, but once you get the hang of it, you can do it to any song :)
Tip: When counting the chords, count the BLACK keys too! :D
Step 3: Finishing
As I said before, it's a little bit tricky at first, but once you get the hang of it, you'll be fine!