SA registering confusion

Hi, This is all very new to me and I'm a little confused, but I'm just trying to get a SA/UTR number for myself as self-employed to work for someone elses company. The sections are: Business details, Business address, Business contact details. But it's asking these questions as if I'm the company and it's my company, which it isn't. Am I understanding this correctly? If you fill in the blanks in these parts, it will say... "As part of the business registration HM Revenue & Customs will automatically enrol and activate the Self-Assessment online service for the business. If you don't want the business to be enrolled for this online service, please tick the checkbox below" Many thanks in advance

Hi,

The business will be you as a sole trader for your self employed work. If you are trading under your own name and from your home address this is the information you will be entering to register for Self Assessment and an UTR.

Thank you.