To add a sink to a unit, follow these steps:
Select the cabinet to which you want to add the sink, and navigate to the left panel, while on the Cabinet tab.
Scroll down and open the Countertop dropdown menu
Therein, select the Add Sink
In the carousel that opens, click on the thumbnail of the sink you want to add.
To access the added sink's properties and customize them,
Click on the sink, and navigate to the left panel
Select the Furniture/Light Unit tab in the left panel
The properties of the sink such as dimensions, positioning and materials, will open up in the left panel for you to customize
To delete the sink,
Click on the sink, and navigate to the left panel
Select the Furniture/Light Unit tab in the left panel
In the left panel, select Remove Furniture/Light Unit.