Here are two different ways to play the begining. The first one is the way I play it, the second is the real way to play it
The first one is easier to play if you can't change frets fast enough

e |----------------|---------------|---------------|---------------|
B |----------------|---------------|---------------|---------------|
G |-----0----------|----0----------|----0----------|----2----------|
D |---4---4---4-0-4|--4---4---4-0-4|--4---4---4-0-4|--2---2---2---4|
A |-2-------2------|0-------0------|2-------2------|4-------4---0--|
E |----------------|---------------|---------------|---------------|
  Original way:

e |----------------|---------------|---------------|---------------|
B |----------------|---------------|---------------|---------------|
G |-----0----------|----0----------|----0----------|----2----------|
D |---4---4---4---4|--4---4---4---4|--4---4---4---4|--2---2---2---2|
A |-2-------2---5--|0-------0---5--|2-------2---5--|4-------4---0--|
E |----------------|---------------|---------------|---------------|