When I was taught this I was told it's the hardest thing to do on bass. This is not 
Just get the timing right and it's easy. Listen to the song to work this out.

G|----------|-------------|----------|-----------|
D|-----9-9--|--------6-6--|6---------|-----------|
A|--7-7-7-7-|--7654-4-4-4-|-4----7-7-|--------9--|
E|----------|-------------|--75-5-5-5|--88--77-7-|

Thats it for the whole song except for when there's a key change for a couple of 
Listen to the song for when this comes and just move one fret up the board. So instead of 
on 7 you start on 8 etc.