To configure the MOFI to act as a bridge, you can use its Passthrough feature.  You can only have one hard-wired device connected and it must be plugged into LAN port 1; the WiFi and other LAN ports are automatically disabled.  When the mode is enabled, the MOFI is like a modem and whatever WAN address is assigned by the carrier is assigned to the device on LAN 1.  
You can setup the MOFI in bridge mode using the IP Passthrough/Bridge configuration page.  Below is a screenshot of that page, followed by instructions.


To enable the mode:

1. On a device connected to the MOFI, open a non-Chrome (e.g. Safari, IE, Firefox) browser to address Login password is admin.

2. Click on MOFI Business > IP Passthrough/Bridge in the left-hand menu.

3. Click the checkbox next to Enabled.

4. Configure any options you want.  For instance, you can specify the DNS server IPs to use or just use those configured from the carrier.

5. Click Save.

6. Click on System > Reboot, then Perform Reboot

After the MOFI comes up after the reboot, the device connected to LAN port 1 will receive everything. If you need access back to the router after it is in Passthrough Mode, close all instances of the browser if it is already open, then open it and go to