Well first thing todo is make sure your employer has no problem with you setting up as SE for weekend work.
Then think of a company name, trot down to the tax office get the forms & register your company, you only get 3 months to do this from date of your first invoice to a customer after that you'll start racking up fines.
Decide when you are going to run your financial year from (mines 4th April), keep a accounts book of outgoing & incomming payments, keep all receipts & invoice copies.
At end of my financial year I tot up the columbs in the accounts book deduct outgoings from incommings ( hope a profit has been made

) put totals into the online self assessment form submit it, Get a reply showing how much tax is due thats it job done. You then get notification in the post of how much & when by you need to pay.
The end of year tax you have to pay as SE can (if it's not a huge ammount) be paid by having your fulltime employment tax code changed. You request this when you do the self assessment form (I do mine on line) & the tax office then notify your fulltime employer of this code change & you see it on your next payslip.
Some useful links:
http://www.hmrc.gov.uk/leaflets/se1.pdf HM Revenue & Customs:Self Assessment Starting up | Business Link
Well first thing todo is make sure your employer has no problem with you setting up as SE for weekend work.
Then think of a company name, trot down to the tax office get the forms & register your company, you only get 3 months to do this from date of your first invoice to a customer after that you'll start racking up fines.
Decide when you are going to run your financial year from (mines 4th April), keep a accounts book of outgoing & incomming payments, keep all receipts & invoice copies.
At end of my financial year I tot up the columbs in the accounts book deduct outgoings from incommings ( hope a profit has been made

) put totals into the online self assessment form submit it, Get a reply showing how much tax is due thats it job done. You then get notification in the post of how much & when by you need to pay.
The end of year tax you have to pay as SE can (if it's not a huge ammount) be paid by having your fulltime employment tax code changed. You request this when you do the self assessment form (I do mine on line) & the tax office then notify your fulltime employer of this code change & you see it on your next payslip.
Some useful links:
http://www.hmrc.gov.uk/leaflets/se1.pdf HM Revenue & Customs:Self Assessment Starting up | Business Link