When working with a meter main system you'll need to change your Main Service Panel type from Standalone panel to Meter main combination panel.
To do so, begin by selecting the MSP Pin from the toolbar.
If you haven't already placed the pin, you'll need to specify the Main Service Panel (MSP) location to proceed. Simply click on canvas where the Main Service Panel (or meter main in this scenario) is located.
In the Properties Panel on the right you'll now see the Main Service Panel properties. Change the Type of Panel by clicking on the box.
A second Type of Panel option will appear in a dropdown menu which you can use to select Meter main combination panel.
Next, specify the meter serial number if needed.
From there you'll progress through your project as normal. When complete, here is an example of a simple meter main array single line diagram.