Well, first ask yourself, "Do I want to use counterpoint in my music because a)I genuinely like the rich history of counterpoint in western harmonic music of the past 400 years or b)because I want to impress somebody (most likely on an internet forum) with my technical SKILLZ."
Not trying to rip you here. I posted the exact same thread as this on ss.org a couple years ago when I was first starting out as a first year student working towards a BA in music. I wasn't interested in learning it for reason A either.
What you have to realize about counterpoint is there is a very loose definition and a strict definition. The loose definition is really basic and it can be used to apply to pretty much any music that involves multiple instruments. The "real" definition is very strict. As in it follows very specific rules. To many it doesn't feel very creative, because the rules are extremely forced. You have to follow the form to the letter.
The trick in applying it (strict counterpoint) in a "metal" context is to not make it feel forced, and while I like Anata, I don't think they succeeded at that (I don't listen to Spawn Of Possesion).
If you are serious about learning counterpoint sign up for music theory classes at your local university. It is NOT an instant gratification kind of thing. You can't learn about it in a couple of posts on an internet forum. And while we have a couple of theory monsters here (Distressed Romeo and Drew are both very good), there is no substitute for actually devoting a proper amount of time to learning it.
I'm not saying that counterpoint can't be applied to metal. Because it can, but when you put in as much time as would be required to properly know the ins and outs of proper complex (3rd species and above) counterpoint the returns (uses in metal guitar) will be extremely diminished. Not to mention the really complex stuff (3rd species and above) requires multiple voices (or guitars in this case), which is impossible to work in a live context without pre recorded parts.
You'll be better off just starting with Western Harmonic Theory (which counterpoint is a huge part of anyways). Before you start doing stuff like counterpoint you have to know the basic skills, such as chord spelling.