How do you pay your own national insurance contribution and tax?

if you working as self-employed?
thanks

Register as self employed on the HMRC website.
You pay the tax half yearly in Jan and July based on the amount assessed via your tax return..

are you working in the construction ? if so 20% will be deducted at source . you need too go to tax office to register as self employed
if not in construction you still need too go to tax office,