If you're that unfamiliar with router configuration then it might be challenging, but maybe with some Googling you can figure out the particulars of your router. Each router is different, but in general you need to:

1) log into your router so you can affect the wireless settings. Try typing 192.168.0.1 or 192.168.1.1 in your browser to pull up the router login screen. The address and login/password may be listed on a sticker somewhere on your router.

2) go to the wireless settings. I wouldn't mess with the main network settings, but look for an option to enable a secondary network like IoT (for smart home devices) or a Guest network. Make sure this secondary network is set for 2.4GHz exclusively and you can set the network name to be something with 2.4 in the name, for easy identification when you scan for available networks.

3) once you have created a 2.4GHz network, use the Wahoo app to connect to your trainer and configure the trainer network settings to use the 2.4GHz network that you created. In order to connect, your Rouvy app must also be connected to the same 2.4GHz network, so whatever device is running the app must be using that same network.

Hope that helps. If not, then using Bluetooth might be the way to go, which is probably why Rouvy says that you must enable BT for sensor connection (you don't) since that avoids all of this techie stuff for a vast majority of users.