Theory of Relativity Explained by a Confused Guy Named Johnny

So, I was trying to explain this whole "relativity" thing to a friend, but I got stuck on the whole "time" thing.

Apparently, time is relative? Like, I can make it relative by moving around it? That's not how I think it works.

Here's a diagram I drew:

A poorly drawn diagram of space-time

See, it's like this: Me am moving around time, making it relative.

But, wait, what about space?

Is that relative too? Or is it like, fixed or something? Help, physics!