Hi SamiUddin
Is the POE switch connected to a router (or anything with a DHCP server)?
Have you tried connecting only one device to the switch at once?
Device_manager is located inside depthai-python/utilities/. You can use it to flash bootloader/applications or change IP addresses seamlessly.
The button is to enter USB mode when connecting directly with USB-C it think.
Thanks,
Jaka