I know when I was self employed, for my very first tax return I made an appointment at my local tax office
Free help although they will not fill out your form for you they will tell you what goes where and you can pencil it all in on the form
I know when I looked at the form it looked like I could never fill it out, but I didn't have to fill out every page, only what was relevant to me. It may be that you only have to fill in a couple of the pages relating to your other income
Maybe give them a call? Can't hurt can it?
Good luck