To create a new Party Group record you will need to navigate to the party section and then press the +.  You will then be provided with the Party Group entry screen ready for you to complete.

Fig 1 - Party Group Form

All the fields on the default Party Group entry screen and their meaning.

Field Name
Party Group#
Unique identifier for the record, generated by the solution
Name of the Party group
The Type of Party Group. The current Value Set will contain a default list of options: Internal/External/Public Limited (Plc)