Rick, if your MC Server is on WiFi only, you may need to do some more work, and it may not be possible if the PC is old. WOL over WiFi wasn't well supported in the past. The Wireless Adapter in your PC needs to specifically support WOL over Wireless. I believe this means it needs specific hardware, and not just the latest drivers.
You may need to find a setting in the PC's BIOS to allow Wake On LAN over Wireless. In fact, Google "Wake On LAN over Wireless" to find lots of information.
If you get stuck, tell us what your PC is, Brand and exact model, or if not a specific brand, motherboard brand and model, or if you have a separate Wireless Adapter in it or a Wireless USB Adapter, brand and specific model.
You don't usually need to make changes in your Router setup to get WOL working. If you were trying to wake the MC Server from the internet, that would be different. You do have your Android phone connected to your home WiFi network, correct? Because if you only have the phone connected to mobile data, that means you are trying to wake it over the internet, which as above is harder and does require changes in your Router, if the Router supports it at all. Many don't.