It's a balancing act between neck relief and saddle height. Neck relief is easy enough. Tighten enough that the strings lay flat on all the frets with the first and last fret held down then very slightly loosen the truss till there is maybe a gap big enough for a piece of paper to slide in at the 12th fret while holding the first and last fret down at the same time. It can be a TINY gap. So small you may not even be able to really see it. I tap on the string at the 12th fret with the first and last frets half and listen fir the sound of the string tapping the fret. The gap on mine is maybe 0.006". TINY!!!
Once you have that, then go to the saddles. Fret the 16th fret and lower the saddle until it buzzes out, then very slightly raise the saddle until it stops buzzing. Fret the 17z 18th, 19 and so on frets near the body one at a time to make sure none are getting choked out. If they are, VERY slightly raise the saddle until they don't buzz. Your action is now as low is it will go without buzzing out (unless you have high or low frets somewhere .)
From here I go to the nut. You'll want guages to set the nut. You can get feeler gauages SUPER cheap at any auto parts store. I cut my nut so that there is 0.015" between the string and frist fret with no frets held down. You "can" go lower, but this set up is already lower than many people will be able to play without unintentional buzzing out. 0.015 let's me make the open strings buzz , IF I WANT, but it's still high enough to play clean as well
You don't need tools for the first 2 steps. It's very easy to do. Watch a couple videos. That alone should get you into a place where you can play clean or clank away at will. You may even find you need to slightly add a little neck relief or saddle height to play clean at all unless you have a very light touch.
Just remember this, if it's buzzing near the head stock, add neck relief , if it's buzzing near the body (bottom of the neck) add saddle height.
It's all very very simple once you understand it.
Don't be scared to slightly go too low. Going a little too low is how you find the limit. Go too low intentionally and then raising the saddles or adding neck relief is the easiest way I've found to get as low an action as possible without tolls for measuring.