FreePBX queues and grouping


I am setting up FreePBX 12.0.63 for now and I am looking for a function to set up different queues. In my old Asterisk I solved it with extensions.conf and queues.conf
I want to set up a queue like 999. When I dial it, it should:

a) dial a group in queue 777 which I already set
b) it should ring for extension A and B instantly and after 30 seconds for extension C.

I havent found this function anywhere. Can somebody give me a hint?