Sassypants

Hey! I'm currently trying to figure this out, I'm a graphic designer but new to coding so I apologise if my questions seem silly. Where do I upload the image I would like to use for the curser? Just on a hidden page on my site? Also where do I write the code, I have gone into advanced settings and copy and pasted into the advanced settings>code injection>header injection but it just shows the code as text on the page. Thanks so much in advance! And again sorry if the questions seem dumb, we all have to start somewhere right :-)