Here are two slightly different ways of doing this ...
For Motorola and P25 ...
From the main menu, select [F]ind -> ystem. Fill out the System ID and System Type; tab over to the RR DB User ID - fill that out. Ditto for the RR DB Password. Press Alt-D to download that system.
For EDACS and MPT1327 ...
From the main menu, select [F]ind -> ystem. Locate the system on the RR DB. In the URL (displayed in the browser's location bar) is the SID - a unique number that identifies each system in the RR DB. Fill out the SID field with that number. Tab down to the RR DB User ID - fill that out. Ditto for the RR DB Password. Press Alt-D to download that system.