Creating bitcoin fork

[Andreasx1]

How to edit bitcoin source code and how to start after?

[aleksej996]

If you don't know how to make a Bitcoin fork then why are you making it exactly?

People make forks because there they think that Bitcoin protocol should be changed in some way. What way do you think Bitcoin protocol should be changed?
When you figure that out, then doing the actual change in the protocol is just a job for a programmer. For that you will need someone who knows C++ well and can spend time learning how Bitcoin Core works.

[GiorgosK]

its kind of funny in anyway that you see it
first understand how the bitcoin protocol works and then try to make a fork
a fork if you don't know what you are doing it does not happen with
instructions a paragraph of instructions on a forum

[ericjarvies2]

If you would like to learn how to setup your very own blockchain, and being understanding how blockchain technology -in general- works, you can head over to Multichain dot com, Cryptonotestarter dot com, and others like it, and simply follow their instructions and learn as you go.  Of course, you'd likely want a few DigitalOcean or Linode hosts up and running, so after your got your genesis block/node up and running, you can deploy a couple more nodes on some other machines/servers.

Have fun.

[CryptoMath_TV]

I can strongly recommend you to read the book

"Mastering Bitcoin: Unlocking Digital Cryptocurrencies" by Andreas M. Antonopoulos (This guy is a genius!)

It talks about the technical sides of Bitcoin, how the programming behind it works, the protocol etc... (and also how you could fork it)
(If you don't have programming experience, you won't have any fun with it though)