|Do you know the SSID (the name the router broadcasts on wifi) for the router? Also the password?|
Does it show up in the list of available wifi access points as viewed in any of your devices?
When you set the router up, did you set up any type of security? Particularly any restrictions as to who can connect to it?
Incidentally, whilst (wisely) you haven't posted the SSID nor its password (more properly called its access control key) here now, avoid doing so at any time. No need of that information - especially the full access key.
You say that on the router itself it shows devices connected to it; where is it showing this information? What is that information?