To add double vertical gola profile handle between two units, follow these steps:
Ensure the two units' sides are flush with each other, so that the shutters are in line with each other.
Ensure that the shutters open in the correct direction. If not, change the shutter toggle direction by following the below link:
Select both the units via Shift+ Select, and navigate to the Cabinet/Corner unit drop down menu, under Common Properties of All Selections in the left hand panel.
Open that dropdown menu, and open the Cabinet Double Vertical Gola dropdown menu. There, select the Add/Change Double Vertical Gola option.
Choose the desired profile from the carousel that opens up, by clicking on the thumbnail. The profile will be loaded in between the two units, with the appropriate gap.