Room 21

e|--------------------------------|
b--------------------------------|
g--------------------------------|
d----5--5-3--5--10-12-10-8-5-5-8-|
a----5--5-3--5--10-12-10-8-5-5-8-|
D|----5--5-3--5--10-12-10-8-5-5-8-| x2

The part that usually comes before the chorus is...
e|-------------------------------------------|
b-------------------------------------------|
g-------------------------------------------|
d---8-8-8-8-8-8-8-8-10-10-10-10-10-10-10-10-|
a---8-8-8-8-8-8-8-8-10-10-10-10-10-10-10-10-|
D|---8-8-8-8-8-8-8-8-10-10-10-10-10-10-10-10-|

You could also do the beggining like this.
e|--------------------------------|
b--------------------------------|
g---------------5-7-5-3-----3----|
d----5--5-3--5--5-7-5-3-5-5-3----|
a----5--5-3--5--3-5-3-1-5-5-1----|
D|----5--5-3--5----------5-5------|

And the part before the chorus like this.
e|-------------------------------------------|
b-------------------------------------------|
g---3-3-3-3-3-3-3-3-5-5-5-5-5-5-5-5---------|
d---3-3-3-3-3-3-3-3-5-5-5-5-5-5-5-5---------|
a---1-1-1-1-1-1-1-1-3-3-3-3-3-3-3-3---------|
D|-------------------------------------------|