This is one of metallicas first big hits. I highly Recomend you learn this
this song, Its awsome. ROCK ON!!!!!!!

H=HAMMER ON
S=SLIDE

E---------------------------------------------------------
B---------------------------------------------------------
G-----------7-(h)8-7--------7-(h)8-7----------------------
D---------------------------------------------------10-7--
A--0-0------------------0----------------0-8-7-10-7-------
E---------------------------------------------------------

BREAK
E---------------------------------------------------------
B-9-7---7----------------------------------------------------
G-----9---9-8-7-7-s-5--------------------------------------------
D---------------------------------------------------------
A----------------------------------------------------------
E---------------------------------------------------------

The main Riff goes like this
E---------------------------------------------------------
B---------------------------------------------------------
G-------------------------------------------------------
D---------------------------------------------------------
A----------5(S)7---5(S)7-------------7-5-------------------------
E--0-0-0-0-3---5---3---5----0-0-0-0-------7-6-------------------------

Thats pretty much the begging, Im 99.9% sure that thats the exact way they play it.