Oh perspective, sweet perspective... Well, I don't know much, but maybe it will be enough to give you a little help.

Before anything, I apology for my grammatical. I'm not... the best with English, but yeah, I'm trying. Oh, and sorry if it is a big explanation too.

- Top View

So, lockers. Lockers are rectangles and the're on the wall, so it make things pretty simple and kinda easy. Like I said, the're rectangles. If you want the vision from the top and you're not used to work with perspective, it's good to draw some grades, the lines that will guide you with the size of things, giving that thing we look for when doing perspective. Something like this:

With that, you can start doing a big box on the bottom and, after that, a bigger version of the same box on the top - always respecting the perspective guide lines. And, after that, it's just connect the front tips of the bigger box, to the smaller box. If you want, you can also do a rectangle and distort till it fits the guide lines, following the proportions of the smaller and the big box.

It would be something like that, on the simple form. And yes, those boxes will be a little deform, 'cause this is what perspective do great part of the time.

Well, after that, you just start making the details of the locker. Of course, again, respecting the guide lines, since the intention its that, make the perspective.

- Side View

The side version it is not different from the top view, since it follows the same rules, but with a different angle. You just need to do the guide lines based on that other view - I drew it a little narrow but I think it still works. Here's an example of the guidelines for this side view and what the rectangle would look like. A big box. And that's it.

I have my own struggles with perspective, but I hope this helps you! If you have any questions, I'll try to answer them the best that I can. Good luck!