you usually need to set up 3 entries.
Chosse a static IP if you can so that you can always browse to your device. Make sure it is not in the DHCP range.
ip = 192.168.0.3 (example)
subnet = 255.255.255.0
gateway = 192.168.0.1 (or whatever your router ip address is)
Can you be specific with any errors thrown up when it tries to connect?
If you are using Ethernet it should see the router, the WPS button is for WiFi.
You need to know what the Ethernet address for your router is, that will clarify your network subnet. Once you know that you can progress. If your AMP can do DHCP try that first as that will get an IP address from the router. In some cases MAC address filtering may be setup on the router but if you set that up you would know how to manage it. If you have a PC run ipconfig command from a DOS box (CMD). That will show all your netword details.
What choices do you have on the AMP for the network options?
Just had a look at the WL300, looks like it is a LAN to Wireless box. If that is so you would not connect that device with a cable to the AMP, the WL300 would need to be connected to the ISP provided Broadband device. Then your only choice is WiFi. So connect the WL300 back to the broadband unit with the cable and try and use DHCP on your AMP to connect to it. As a test does your mobile phone see the SSID of the WL300 (ie does it see a WiFi network) ? If your mobile phone can connect to it so should your AMP