Good day @nevstugt,
That's strange, maybe it simply means that network has no access to internet. Have you tried to connect to the brain with ssh or any GCS anyways? If you have the chance I'd try to use Ubuntu (pref 14.04) to work with the Erle Brain.
You need a DHCP service running on your network (most if not all current home routers come with this among many more services) for the brain to get an IP when connecting it to said network with an ethernet cable. You should get an IP after waiting for a bit when connecting the ethernet cable to the brain. If not, there might be a problem on your network, or maybe it's the intended behavior with the configuration the router has. Are you working on your home network? Do you have access to it's configuration? If you don't have to configure anything when trying to connect a new phone or pc to your network this shouldn't be the problem.
How are you connecting everything? The EB3's ethernet should be connected to the network, not directly to the pc.
You could move forward this way (once the brain properly connects to the network, has an IP...), you'll need to indicate to the brain what IP your computer has (a fixed IP in your pc greatly simplifies this as you wouldn't need to update this for each execution). You should just need to modify the
~/apm.sh script to specify it changing the following line from:
$APM_BIN_DIR/APMrover2.elf -A udp:$wifi -B /dev/ttyS0 $FLAGS
$APM_BIN_DIR/APMrover2.elf -A udp:192.168.1.10 -B /dev/ttyS0 $FLAGS
(Change 192.168.1.10 with your PC's IP)
Personally I'd focus on fixing the wifi connectivity issue.
Connecting to GCS is only necessary if you didn't get a ready-to-use SD from us with an autopilot installed. If that's the case you'll need to connect with a GCS to parametrize your autopilot after installing the autopilot binary. Those parameters are specific to the vehicles we offer and may give problems or plainly not work with other hardware.