If you can handle your way around MsPaint you can take the basics of tools and it's really alot the same in Photoshop.
Though Photoshop is heavier, has alot more features and is more advanced. Basics it's the same.
What I suggest is just try the basic tools out first. Paint brush, pencil, eraser, paint bucket and gradients. Then try to make a new layer and paint a bit on it. The try to click the little eye that's on it. That'll describe what a layer is pretty good.
When you know how to use those go for the tutorials.