BEAD tuning low to high for 4 stringers,BEADG low to high for 5 string(basic 5 string tuning!) On 
this album Rayna uses a pick on it seems like all the songs,including this one,but using your fingers sounds good too.

Main Riff:
D|
A|
E|
B|0-0-8-8-7-7-8-8-7-0-

Play the same thing throughout the whole song...