What is it for on a laptop?

What is that for

This is a keyboard for entering commands.

You can also use it to move the mouse pointer. Some people find it more comfortable than the touchpad.

Digga this part there

Do you mean the blue part there? A cursor-mouse replacement

This is a touch pad to control the mouse.

It's a built-in mouse.

Aloha!

You can use it to move the mouse. Nowadays you rarely find something like that, because almost nobody really liked to use it. The trackpads just keep getting better in laptops.