Where to gather necessary information for developing an ZigBee Hub device


I’m an engineering student doing a project with the XBee3 dev. kit trying to build a HUB which can connect with compatible zigbee devices.

Basically I want to be able to connect many Zigbee end devices, and process the transmitted data. How do I recognize the data (API mode - frame data) I actually receive from e.g. a motion sensor. Do I need to contact each devices manufacturer if I want to support the devices and hope the manufacturer will send me a datasheet stating in which order the data is provided?

What is the usuall development flow when creating such a devices? I am on a rather harsh time plan because of the limited weeks in a semester.