Registering as self employed?

[ChocolateGanache]

I understand that you need to register as a sole trader with HMRC… but what happens next?

(apologies if this is a silly question . I have never done this before )

You register as a sole trader and they then give you a login to self assessment online which enables you to manage your tax returns every year. Currently, that's once a year, but they are trying to roll out a system called Making Tax Digital which would require some businesses to report quarterly. It's been massively delayed and may not apply to you initially (based on turnover, VAT status, type of business etc).

Your council may provide free training for setting up a new business as a sole trader which covers things other than just tax/HMRC.

Keep good records - accounting packages like quick books or xero help. Save your tax money from day 1, I put 20% of any income directly into a restricted access savings account for tax. I put another 10% into an instant access account and this is my holiday money and 10% into my pension.
From day 1 be on top of overdue invoices and chase hard to ensure you get paid.
do research know what business expenses are allowable for your industry. For example I have been to Thailand to volunteer teaching less experienced colleagues this counts as my continuing professional development so I can claim the flight and the volunteering fee as that covers my food.