Offline as in only available on the computer you are currently using? Hercules, by default, already binds to localhost (127.0.0.1) so there's no extra configuration required: no need to open ports anywhere, no need to register a domain name, no need to get a VPS. Just follow the official instructions:
README.md
BTW, since you are on Windows 10, you don't have to install that oh-so-bulky Visual Studio, you can just enable the
Windows Subsystem for Linux (WSL) and follow the Linux installation instructions instead of the Windows ones.