DHCP (Dynamic Host Configuration Protocol) is a protocol used to provide quick, automatic, and central management for the distribution of IP addresses within a network.
AmberPRO comes with DHCP enabled by default on Amber Router, as this is standard/default across routers. AmberPRO is intended to be the default router and can also be configured to work behind an existing router. Please see this article for configuring AmberPRO to work behind an existing router.
Set to bridge mode using Amber Manager: How do I set Amber Router to Bridge Mode using Amber Manager?
Video tutorial for Amber Manager: How to change to bridge mode
You can also set to disable DHCP here: How do I disable or re-enable DHCP?