You have to do a few things.
First, set your pickup switch to the bridge pickup. This is normally the default for chunky rhythms in rock and metal.
Can you read tab? You're going to want to play a power chord, it loos like this:
D ----------- -3-2-------
A -2-2-3-5- -1-0-3-2--
E -0-0-1-3-- ------1-0---
These are the bottom three strings of the guitar, the number indicates what fret you're pressing down on, and a 0 means you strum it, but don't fret that string. Usually I use my index finger (pointer finger) for the lower note and my ring finger for the higher note.
Dial up some distortion. If you strum the chord, it will sound good, but not chunky, not yet. You'll need to palm-mute.
Rest your palm against the bridge of the guitar - you'll want the fleshy part of your palm to just barely touch the strings, an event amount on each string. Too much palm-muting makes the chord sound "dead" (dampens it too much) and too little won't sound chunky.
The thing that many guitarists don't focus on is left-hand technique, though - when you strum you should use *both* hands to control the duration of the chord - for a short, quick chord stab you'll want to lift your fingers off the frets just a little bit so the notes don't ring out, this kills the string vibration and cuts the chord short. Not off the strings, but the frets, if you catch my meaning.
So... you can do this with any note, any chord, it's just that power chords are the most common. Practice your palm-muting on every string, with single notes at first, then chords later on. It takes some time to learn how to play it well - you can't palm-mute very much on higher strings, as even a little bit too much will kill the note completely, etc.
When you do palm-mute and do stuff like this, only play the notes that you want to ring out - don't *strum* the guitar, only play the 1-3 strings that you want to sound. Use your left hand to mute the other strings so they don't ring out, by resting it over those strings that you want muffled.
There are a lot of little things that go into making a palm-mute sound *good*.... just about anybody can palm-mute, with enough practice, but doing it well takes some effort.
Good luck - keep practicing!
You can youtube "palm muting" for videos, too, if this was confusing.