How to declare additional income for freelance work done locally?

I did some freelance web design work on a once-off basis for a local company, how should I declare this income on my tax return?

You must declare it under "Local Business Trade and Professional Income". Remember to declare any business related expenses incurred in earning this income too.

Please see information below on provisional tax should you decide to do more of this type of work in future.
Am I a Provisional taxpayer?
What is Provisional Tax? How and when?