The challenge is usually that your firewall or router will not route broadcast-packets from the Internet to your internal LAN. The WOL-Agent solves this problem. The agent is a small service that you install on any available Windows server on your LAN. It listens for WOL packets and then translates them into broadcast packets and sends them back into your LAN. This solves the problem of firewalls and routers that cannot forward broadcast type messages.
This is how the traffic will flow from the client to the agent and to the LAN.
The final step is to configure WOL to send packets to the computer that is running the agent.