First time freelance consultant from January 2016 - do I register for provisional tax?

I just started as freelance consultant in Jan 2016. I am not sure how much I will earn as it all depends on if I get clients. Do I register for provisional tax? From reading your articles seem I fall in the 2nd payment what do I do? SARS assumes taxpayer will be able to pay upfront?

How much will you be earning in profit after expenses for the 2016 tax year?

Expecting income of least R25,000 a month. not sure of cost may be R5000 roughly. Do I need accountant letter to show that estimated income and expenditure?

You will need to register as a Provisional Taxpayer as your net income from other work is more than R30 000 per year.