And try some coding (I found a board for the coding already, so I thought I would use that). However, before I start, I wanted to know if anyone had any suggestions for the size of the background, or how I ought to go about tackling this.

I have never tried this before, and I wanted to know a good place to start for size, and any other kind of hints or ideas/suggestions to make this as easy as possible. Thank you for helping if you can!

(I did not find any board like this, but I could be blind)

If by 'background' you mean the overall design for your CSS where everything will go, I'd say a generic size is about 900x900px :) but it varies on the shape and design of your profile.

All I normally do is take a screenshot of my profile and crop to the right size. It's probably not the best way to do it but ah well, as long as it looks good on my screen I guess ^^'

Also!

Usually I go for a 1024x768 resolution but you may want to make it smaller. As for suggestions, I'd say avoid to make something that "cuts" at the end. Make something that can blend in the background color. And save in png rather than jpeg ^^

Thank you both :) I will try it out more this weekend.