I have no router

at least the ones that you play in broswers

I've noticed that my computers have same IP address

It seems that you need to read up on:
- how IP, UDP, and TCP addressing works
- how sockets networking versus browser networking works
- how Internet routing works
- what NAT is
- and what "internal" versus "external" IP addresses are in the context of NAT

Once you've read up on those things, you should be easily able to figure out your original problem.