How do I enter GST?

Thank you, for your question!

To enter GST you must open your income tax return, from there on your left hand side you will 

1. Click on Income
2. Scroll down to self-employment 
3. Click on self-employment profile
4. Answer the questions and continue 
5. You will be now on your business T2125 
6. Scroll down, till you see GST