From outside, you can connect only to your external address, provided by your Internet Service Provider (ISP).
If you connect from outside to that external address, your router needs to know which of your internal servers is the intended destination. That is where port forwarding comes in. You must tell your router something like this:
"If you receive a connection for port 80, please forward it to 192.168.1.134 port 80."
Then, the connection from outside will go to your ESP.
If you want more details, search the web for "Network Address Translation" or "NAT".