It depends on what network management tool your distro is using, (but dhclient and dhcpd are two possibilities). Ordinarily the router contains a DHCP server, and so a default DHCP configuration on the client is all that is required.

Ok, the 'ip route' info confirms that the router address is 192.168.225.1, so try that address in a browser.

Sorry but what makes the the computers address have the same network as the router? Something has to make them the same right?

Yes, DHCP takes care of that. Very basically, when first connected, your PC will send out a 'dhcp request', and the listening server will respond accordingly with offer of a lease. Ultimately, that's how the PC get's the IP address and default route needed to get connectivity.

Is the computer and modem directly connected via patch or crossover cable?



Power down everything. Power back up with directly attached modem.
I'd make computer static ip in some subnet. 10.10 or 192. or whatever.
Make a class subnet.
Make static arp entry using the modem's mac in that subnet you created.
Use the static ip entry in browser to see if you can access the management page.

I'm trying to manually configure the NetWork Manager at this point.
192.168.225.1 does not work to open the Dash Board.