Hi Lean,
It's possible, if they're on the same network. But this is a more general networking question, and not something Review Board-specific. Review Board itself isn't able to control whether it's available on your network, so there's not anything you can modify there to make this happen.
The biggest challenge, since you're hosting on WSL, is to make the Apache port (80 or 443) accessible over your network. Normally, WSL is protected by both a firewall and by kind of being on its own private network. That's where step 2 in my instructions comes in. You'll need to follow Microsoft's instructions for making ports 80 and 443 available on your network (aka "adding a route"). At that point, other computers should be able to access it using your Windows PC's IP address.
The firewall changes also need to be made on the Windows PC. Those dictate what ports other computers are allowed to access.
WSL makes this a bit more complicated. If you were installing on Ubuntu itself, you might have an easier time. But it's doable.
Christian