Income tax requested for DTV application - not having one since being a nomad:

Got requested - Financial evidence: an amount of no less than 500,000 THB, (e.g., bank statements for the last three months, sponsor letter) (already provided)

+ Provide the salary slips/income for the past 6 months, please highlight them in your transaction records, and provide your income tax last 2 years.

I have 2 questions:

1. Since, I've been moving around multiple countries (less than 6months each country) - It wasn't required by any of these countries to pay income taxes - what should I attach as income tax for the last 2 years?

2. I attached the bank statements for 3 months with over 500.000vnd.

Now that I will have to attach the payslips for the past 6 months, should I just highlight them in that 3 months bank statement - or should I attach another 6 months transaction record which I haven't got?