[acetboy]

Where to start? All of those things you're asking questions about can be googled.
I'm sure you could spend hours/days reading things and looking at You Tube videos.
Which is all a good place to start.

I get the impression you need to learn a lot of basics about audio in general and digital audio in particular.

I bought my first computer in 2005. That's kind of late.
I also bought Pro Tools LE on the same day from the same dealer.
I had been spending years reading music/instrument magazines and books.
I already had spent years owning audio equipment like keyboards and mixers and various
types of recorders.
I had several samplers one of which my Kurzweil showed a small waveform in it's screen for editing.
I read about Pro Tools for a number of years before I bought that first computer.
So I knew basically what I was going to do even though I had never done it. lol

My idea was that I was going to be creating music of my own. LOL Big ideas. LOL
Well I did from the start began recording my friends who have a punky garage band.
That helped.

And soon after I got that computer I did figure out all about bit torrent and all of these sites
we all love.

And pretty quick I did discover that much of the music that's shared be it old recordings that
have been shared for years and years or new captures that people were putting up, much of
this music has various issues that could be corrected.

I got the rudiments down fairly quickly but then I spent several years developing the techniques that I use. And then several more years to get half-way good.
And I think I'm getting better all the time, or I'm trying to anyway.

So you need some decent monitors/speakers. They don't have to be huge or incredibly
expensive but you have to learn what they sound like. Listen to lots of your favorite CD's
legitimate releases. And it helps to put your favorite music from those cd's into an audio editor and learn that way what a waveform looks like. Learn what spectral views of legitimate releases look like. Learn what the FFT views of your favorite music looks like.
Your masters/remasters should look much like a legitimate release looks like.

Audacity is a good app to start with, it's free and there's lots of info on it available.
I've recently discovered another free app called ocenaudio. I really like that one for it's
FFT views and spectral views.

Learn how to use low pass and high pass filters. If you apply a low pass filter at 120 Hz
that will cut off everything above that point and you'll just hear the low end.
And you can then look at the low end only, see what the waveform looks like.
Maybe the first half of a show has a good strong low end but then the latter half
suddenly loses the low end. You can do the same with a High pass filter at 8000 Hz
and see/hear nothing but the high end. What's going on up there? Is it strong or lacking?
Is one channel louder than the other?

And then by using low and high pass filters together you can isolate various frequency bands
and see what's going on there say in the upper mids.
And you might see/hear that even though the low end is fine phase wise up here in the
upper mids it's gone out of phase. Very common thing with external microphones.

So that's all I got now, good luck.