How to deal with tax as a self-employed performer
Tax as a self-employed performer should be dealt in the same way as any other self-employed job. Your first point of call is to register as self-employed with Her Majesty's Revenue and Customs (HMRC), or whatever body deals with taxes in your location. This is a simple process that can be completed online. You will be required to give your personal details and some information regarding the type of self-employed work you're involved in. Once this is complete you should receive a Unique Taxpayers Reference number (UTR). Be patient, sometimes it can take up to six weeks for this to arrive. This ten digit number is effectively your tax code. You should provide it along with your National Insurance number each time you get a job.
After this it is simply a matter keeping all of your invoices, payslips and expenses receipts for self-assessment. This is sometimes easier said than done. It is entirely up to you to keep track of this and make sure you contain proof of payment for every job you do. If you haven't received an invoice or payslip request one. Legally you are entitled to one so there should be no issue in asking if you haven't received one.
Self-assessment is done once a year (the deadline is usually around January), this is when you determine what tax you owe for the year, based on the earnings from your invoices etc. Hiring an accountant for this is bit would be the safest option. While it is not terribly difficult it is best to avoid any potential fines from the tax office for any errors. The cost of an accountant for this one time job is massively cheaper than paying a fine. Though it is not necessity. If you feel confident you can do your self-assessment yourself.