How does one start their own VC or become a angel investor, through what source or platforms angel investor can find businesses that they intend to support or become part of?

Ans: To become an investor into start-ups, you first need to have investible surplus that you can afford to lose without losing any sleep! It is a high risk activity involving patient capital; further it is illiquid and returns are uncertain. It is essential to understand that. Some investors also like to play an active role in some of the start-ups they invest in.
How do they find businesses to invest in? By being close to the places which start-ups frequent. It could be incubators, accelerators, entrepreneur facilitation bodies, associations etc. Many investors become part of angel networks, syndicates etc to understand how other experienced investors evaluate and invest in start-ups. It would be good for you to speak to a couple of experienced investors and financial advisors before you embark on this journey