i wanna white my teeth and fix my 2 chipped front teeth . . . . . . what should i do first?

When I was little, I was never disciplined nor was I taught the habit of tooth brushing.

I’m suffering the consequences in my teen years with nasty teeth. They’re not bad per se, nor extremely yellow or anything, but they’re not the healthy white. The teeth in the front of my mouth look OK, but the ones in the back have some noticeable cavity work – it’s really off-putting for me, and I think some of those teeth emit a smell.

I brush my teeth regularly, I’ve started doing that for some time now, but I think there is some sort of undetectable layer of nastiness on all of my teeth that I can’t take off.

Is there a way I can treat this? Like, will the apparent smell go away if I just brush regularly for some years? And if I brush normally, will the teeth eventually lose the light yellow color that I gained from my youth? Are there any solutions for this?