Ste dav

Hi, not sure if this is the correct place or how to generate a new question, so apologies if incorrect. In short I am full time employed and currently pay tax via my employers PAYE. I will continue to to work full time but am looking to set up as a sole trader. Do I reg first as a sole trader, then self assessment? I haven’t started selling yet but would like to do so as soon as possible. If I reg before the end of this tax year, i.e April, will I still have to complete a self assessment, even though I have not sold anything?