How to make a usb and network spread ransomware?

[myappli12a]

I've done a lot of research on this but couldn't find enough resources or a working example. A method or a tool that we will explore together here will be very useful for all of us. How is it possible for a software to spread over the network? How can it copy itself to all 4 shared computers on a network and run there? Or how can it automatically run itself on the next computer by spreading from the usb. Is there such a tool already created?

example:

1. select exe file
2. build with spreader
3. you are done!

 

[introvert]

I will like to know how it really works