Here we see the main guitar parts for Sad But True by Metallica. This is one of their easier songs to play, and is about as beginner-friendly as Metallica get. The song is in D tuning, which means downtuning each string by 2 frets (from standard tuning) to:

Low D : G : C : F : A : D

We show the first half of the song, up to the solo. That's because every riff you need for the song is contained in this section of the song. After that it's just repeats of the same riffs.

Intro - The Intro is quite short and simple. It's the same powerchord sequence repeated twice, with a different 'tail' each time.

The first tail ends with a trill (hammer / pull off combination).

The second tail ends with a powerchord stab and abrupt mute.

Verse Riff 1 - The verse riff is short, sweet and repetitive. Break it into 2 chunks. The first chunk is just 3 powerchord chugs, and the second chunk is a little descending pull off lick. Occasionally they play this alternate lick instead.

Notice that during the riff that the powerchords are muted. You can use any finger / thumb to mute the strings, plus use your picking hand to kill the strings. As long as you get the dead stop between chords, that's the important thing.

Verse Riff 2 - The band switch to playing this riff for the second half of each verse. It's another short riff which repeats a lot.

Chorus - This riff is a little bit longer than the other riffs, but just as repetitive. It's nice and straightforward powerchords for the most part. The trick is more in getting the picking right with your rhythm hand.

Chorus Harmony - During each chorus the lead guitar plays this little harmony over the previous riff.

Interlude - This comes before the solo. First we show what the rhythm guitar plays, just keep repeating these powerchords. Next, we switch to showing what the harmony guitar plays over the top of this riff.

After this the song just keeps repeating the same riffs over and over again, and Kirk starts his solo. We'll see that in the next ActionTab.