Hi jaga.
Welcome to this family. I will give you some advice.

The black wires connected to terminals marked 24 VAC. Not needed in Imolaza, trace them back and unplug the transformer. Imolaza has its own transformer that should be used.
All those red cables across the top are zones 1 through 7. Those go to the corresponding Imolaza zones.
Those three white cables are kind of hard to figure out. The terminal with two white cables must be an "RS" terminal. The "C" terminal is next to it. So you must have a rain sensor which requires connecting the "RS" terminal and the "C" terminal. So one white cable left, refer to the hunter src manual, "Connect the valve common from the field to the RS terminal. If a pump relay is being used, the pump relay common must
also be connected to the RS terminal." Do you have a master valve or PSR?

jaga Oh, I see, you don't connect to the "MV" terminal...
So one for the rain sensor, one for the valve common. I got it. It's easy to figure out.
You can just pull off a white wire that is connected to the RS port. Then test the zone, if the zone can be activated, it means that the white cable left on the "RS" terminal should be connected to the "COM" terminal of the Imolaza. If the zone does not operate, then the white cable left on the "RS" should be connected to the "S" terminal of the Imolaza.

Am I clear enough?