This really is not a code related question; it is the configuration of your computer and/or network.
1. Configure IIS and Windows firewall to allow connections to your computer.
2. Configure your router to allow requests to your computer
Both of these are going to depend on your particular setup (OS versions, router brands), but here are some links to get you started.
Access Website Hosted In IIS On Windows 10 From Any PC On LAN
Setup A Virtual Server In The Router - Web Server DIY Tutorial