Can anyone help me out here?

 

I think the main verse is

 

[Am] [c]

 

D D U D D D U U D D

 

But it doesn't sound right and the riff doesn't end there, the problem with it is I think theres an enthisis on some chords. I also don't know the timing.

 

This is the very first song I've ever tried to learn, so can someone give me the pattern and if applicable the hammer / silenced notes and timing.

Yes, the verse chords are Am, C or C/G, Em, Am. You can play it in standard tuning or EADGBC, which I think sounds best

(the C/G is a standard C with a G bass - to achieve this, you put the pinky finger on the E-string's 3rd fret. If you find this difficult, just play the standard C).

 

I think that when Chris plays it, he emphasises (?) the first upward stroke, and the pattern is something like this:

d---d--U-u-d--u-d-u

 

Just keep on playing, and the strumming and timing will improve.