Hi
For income tax purposes, advance tax can be calculated on the basis of expected annual income. Advance tax becomes applicable if your expected annual taxes are above Rs. 10000.
You will need to estimate annual income on the basis of income already earned in the year and pay advance tax accordingly. Calculations may be done by you or we may help you with it on a separately chargeable basis.
Expenses which are directly related to you business shall be allowed as deductions.
For GST, you don't need a GST registration till your turnover exceeds Rs. 20 lacs.