Yes, you can use Amber behind your existing router by setting Amber to Bridge Mode. To do so, please follow the steps below:
1. Connect to Amber's network with your computer by using an ethernet cable or Wi-Fi.
2. Open a web browser and go to latticerouter.local and login to Amber router (default password is admin1234).
3. Go to WAN, change connection mode to Bridge Mode and click Apply. If bridge mode cannot be applied or not shown, please update Amber Router firmware (see here).
Note: Once bridge mode is switched router will reboot and DHCP will be done by the primary router.