I've watched the tutorials and videos but it simply doesn't appear in my color palette where it does within the videos. Could someone please help me?
Have you checked that you are opening AE1.5
Assume you have.
So you select a box and create a rectangle, with it selected look at properties panel - colour. I see a solid box on the left, in the middle a grad box with a line through it, and the border line
with the rectangle element selected, click on the middle box and thats your grad.
If that is all teaching grannies how to suck eggs, my apologies.
If you have 1.5 and you're not seeing that bos I've described, delete and re-install :-(