When buying 5% or 7%, or 9%, and do on up to less than 25% of the total shares of a company, disclosure need to be made to SEBI.  
The same needs to be done when 2% or more shares are sold.  
Kindly guide a beginner retail investor as to:
Q1. When will I file, the day I trade or T+2 day when I receive the stocks in my demat account?
Q2. If I buy overnight CNC futures of the stock and hold till expiry, when will I file - on the expiry day or when I receive the stocks in my demat account?
Q3. How to file the disclosure as a retail and individual trader?
Do we do it by ourselves online, a broker, a chartered accountant, or the company’s RTA?
Q4. Any other paperwork, regulation, laws required to be complied with after acquiring substantial shares of a company?
 SEBI Takeover Code - YouTube
 SEBI | Securities and Exchange Board of India (Substantial Acquisition of Shares and Takeovers) Regulations, 2011 [Last amended on December 06, 2021]]