Configure openHAB2 for Homemazic

Hi,

I installed OpenHAB2 on raspi and added the homematic binding using the paper UI. Than I could connect to my Homematic CCU2 and all devices were imported automatically. Now I would like to organize the “things” since they are organized as a plain list. What is the way to organize the item in openhab2? I could not find a config file that contained all things.

Thanks!