b4 playing this song, you have tone your guitar a drop D
(means #6 string in a 7th fret should be same tone with #5 open)
~
|---------------------------------------|
|---------------------------------------|
|---------------------------------------|
|-7----------3---5-----7----------3---5-|
|-7----------3---5-----7----------3---5-|
|-7----------3---5-----7----------3---5-|
[ Tab from: http://www.guitaretab.com/numeric/40-below-summer/28811.html ]
~
|---------------------------------------|
|---------------------------------------|
|---------------------------------------|
|-7----------3---5-----7----------3---5-|
|-7----------3---5-----7----------3---5-|
|-7----------3---5-----7----------3---5-|
|-7-7------------------||-7-7---------------|
|-----7-7--9-9-9--5-5--||-----7-7--9-9-9----|
|----------------------||----------------7--|
|----------------------||-------------------|
|----------------------||-------------------|
|----------------------||-------------------|
|-7-7------------------||-7-7---------------|
|-----7-7--9-9-9--5-5--||-----7-7--9-9-9----|
|----------------------||----------------7--|
|----------------------||-------------------|
|----------------------||-------------------|
|----------------------||-------------------|