That's so simple. I just wasn't thinking it through very well. Thanks.
OK it wasn't so simple. I set the ip address from 192.168.0.100 to 192.168.1.100. I lost the connection and had to turn the thing on and off again to connect. Fortunately it started mining right away and I was able to log in with the laptop. But how do I log in without the laptop using my wifi network?
Ok, so you want to log into the Avalon unit wirelessly? Meaning you want it to be wirelessly connected to your home network?
If so manually assign the WWAN interface (in the network tab) the IP address 192.168.1.100 , set the subnet mask to 255.255.255.0 and the default gateway to 192.168.1.1 (which I'm assuming is the IP address of your router). DNS server can be set to 192.168.1.1 (once again the IP address of your router which acts as a DNS forwarder).
If you do this make sure you remove any IP settings from the Avalon's LAN interface that way you don't get any IP conflicts (which you would get if you give both interfaces the same IP).
If you can I'd recommend connecting your Avalon miner to your home network via an Ethernet cable as it's a far more reliable connection.
Also, bear in mind that what you are being instructed to do isn't definitively "the answer". If you move the Avalon to a different network, your settings may or may not work, depending on the way that particular network has been set up. allinvain has given you typical instructions for a regular household network, but not every regular household network gets set up in the typical way! So, be prepared for a possible change to all of this stuff again!