@Carmen802 at the start of the process you customise the form to your specific needs. If you say you are employed then you need to fill out the income received and tax Paid. Same with shares or interest bearing accounts. Did you click the link in my second post? If so it might help to read the whole document.
@Carmen802 The fact that the rent a room scheme is discussed in the property manual suggests you need o fill in the property sections of the tax return.