First of all 'hello everybody!' as I am new here.

I tried to find the answer in the previous topics but it seems to be my case is a bit different.

I have a permanent contract with my swiss employee ('B' permit) and also wanted to have an additional income as a sole trader (I need my employer acceptance first which should be fine). As I B permit holder I am not declaring my incomes at the end of each year. The taxes are deducted on a monthly basis.

I have three questions:
1. As soon as I will become a sole trader, should I declare my revenues from my business activity separately from my salary filling the annual list of incomes?

2. Should I open a separate bank account to handle my sole trader activity?

3. Should I change my AVS and pay something in addition (I already have AVS as I am employed)?

I will be grateful for all your suggestions.