Sound level values / waveform peaks p...

This is pretty basic and I sure need to understand this. Let's take Audacity, for instance.

Looking at two tracks on the screen. Recorded on Fostex MR-8. I'm looking at waveforms. To left of waveforum is a scale:

1.0
0.5
0.0
-0.5
-1.0

QUESTION: What does this MEAN?

Okay, then up to upper right of screen is this meter thing... two horizontal bars where the signal jumps back and forth horizontally and the peak signals are going to the right. The scale on that is:

-60 -48 -36 -24 -12 0

I assume it's a -60 and a -48 there because that fits the scale increments but there's two icons in the way there, so it's not labeled as such. But it has to be.

QUESTION: What does THIS scale mean?

I'm confused about peaking signals, distortion, too hot a signal... I have been having trouble getting the right levels. Like in this one, I look at the complete waveform, and all is well. I guess. I mean, it's nothing peaked up to the 1.0 or down to the -1.0 level. The peaks are about at 0.6, couple of them to 0.75. If that makes sense. Not even approaching the 1.0 level.

So, I removed the second track so I can look at just track 1. I play it. On that horizontal dual bar at top right, everything is staying maxed out at about -3 to -6, if I am reading that correctly. Even at top peaks, it never gets to 0.

I removed that track and put the othe track up. Same thing. Same levels.

Then, I put both tracks up at same time and play them. Uhoh, horizontal meter, it hits red. It goes all the way to zero quite often and it's like it's trying to bounce off to the right higher than 0.

I don't understand this. Is this bad? Even thought the individual tracks look okay... they don't hit the red... but the two tracks together do? I can't hear any distortion. The two tracks were recorded at same time on keyboard, one to Track 1 on Fostex, other to Track 2.