score:3
how do I explain this in my application?
You answered the question yourself in your subsequent question, i.e. you attach the statement from your brokerage account which show dividend payments etc. When we say bank statements, we do not only refer to traditional bank statements but also financial statements showing your liquidity. I personally keep very little in my checking account, most of my liquidity is in my brokerage account and I always include those. The one time I did not include my brokerage account, my application got denied.
Do I need to attach the contract notes for those specific transactions or is there any other way?
Yes, that is what we call providing provenance of funds.
Do I need to show statements from both salary and savings account in this case?
It makes sense, so the connection between the two will be apparent.
Also I shift most of my salary to my savings account, so there is only minimum balance maintained in this salary account. Do I need to show statements from both salary and savings account in this case?
Yes