C++ :: SDL - How To Handle Mouse Motion Input

I am using SDL 2.0. But I don't know how to handle mouse input. Do you think you can explain of how to do that? Or give me a link that explains that really great?

I know how to handle a mouse button that presses down for a sec.

Code:
if (event.type == SDL_MOUSEBUTTONDOWN){
if (event.button.button == SDL_BUTTON_LEFT){
// Do something . . .
}
}

But not how to handle the mouse input of what the mouse is hovering over and that.

Like in a start menu of a game. I want a button for example to appear blue when I hover over it and when I click on it. It should start the game for example.