Filter Hosts and Whitelist
Every Module has a Filter Section. Here you can Blacklist/ Whitelist the Hosts you want to export, and do the same for Labels/ Attributes which you wan't to export along them.
The Syncer will may have hundreds of Attributes for a host. Normally, you don't want to have them all, for example as Label in Checkmk. Therefore, you have to whitelist them here.