Help on gradients please.

Mainly how to get multiple colours in a radial gradient I can get one colour for a radial gradient, but I can't seem to be able to add multiple colours to a single radial gradient. There is not graph that shows how many colours I'm using, nor the sliders such ...

I can't upload .cur files?

It says something like "missing or invalid cursor file" I don't understand what could be the issue since I'm certain it's a .cur type. Could anyone help me?