In a Uniden HP style radio, favorites lists contain systems. Systems can be trunk systems or conventional systems. Systems contain departments (with the addition of also having sites, if the system is a trunked system). Departments contain Channels, which are either individual frequencies, or talkgroups.
Here's a couple examples from the RRDB (excuse me if this is stuff you already know, but there are folks in this thread who don't, and could benefit):
Ohio MARCS-IP: Multi-Agency Radio Communications (P25) Trunking System, Various, Ohio - Scanner Frequencies
MARCS-IP is a System
. You could put it in a favorites list.
Inside the MARCS-IP system, you will have all the sites, plus you will have several Departments
. Examples of Departments include: Ohio EMA, Statewide Mutual Aid, Athens County (05), etc.
Inside those Departments are Channels
. Inside Ohio EMA are Channels named XEMA-CONW, XNUC-PERRY, and so on.
On the HP radio display (including both the HP1 and the x36HP radios), line 1 would be MARCS-IP, line 2 would be Ohio EMA, and line 3 would be XEMA-CONW.
Similarly, in Cuyahoga County, for conventional frequencies...
Cuyahoga County, Ohio (OH) Scanner Frequencies and Radio Frequency Reference
is Cuyahoga County (abbreviated to "Cuyahoga" in the DB)..
could be "Cuyahoga County Engineer".
inside that department would be "County Engineer - East" and "County Engineer - West".
(Just for the sake of interest on that last one - the HP line of scanners doesn't take the RRDB's "Alpha Tag" field (block of text) into consideration, just the "Description". So the fact that those channels are listed as 1, 2, 3, and 4 in the Alpha field is not brought into the HP. DB admins may want to make sure the "Description" is as descriptive as the "Alpha Tag" is.)
Now, having said all this, all of your Systems are gathered into one Favorites list. You can have, as was said above, up to 256 different Favorites lists in the radio, and you can choose to monitor one, many, all, or none of them, as well as the "Full Database", meaning that which is already in the RadioReference DB. At least one of those must be turned on - so you can listen to the full DB and all, some, or none of your favorites, or you can listen to all, some, or one of your favorites, without the full DB.