Play in a steady beat but in an up and down stroke..... as in the first chord hit down then on the second hit coming back up then third hit while going back down and so on.....

G:--------------------------------------
D:--------------------------------------
A:----------2-2-4-2-5-2-4-5-4-2---------
E:--0-0-3-4---------------------3-4-----

you can use any two strings .... this is just an example