Profiles are groups of mappings and settings that when active will define what all of the Zs various inputs and outputs do.

Your current profiles are listed along the top of the driver. The profile currently active on your Z will be marked by an *, while the profile you are currently viewing in the driver will be highlighted in yellow. 

The Profile Hierarchy  

There are three "levels" of profile which work in a kind of hierarchy. 

Global Default is the ‘Grandfather’ of all profiles -  any mappings set up in Global Defaults carry through to all profiles unless they are specifically overridden in that profile.

For instance if you set DPI in the Global Defaults, then this will apply to all profiles, unless you have set a special DPI setting just for that profile.

This is how the Z's config mode works. It is assigned to "Tilt Right 25°" in the Global Defaults profile, so its mappings will apply to all profiles unless they have their own "Tilt Right 25°" input to overwrite it.

The profiles next to ‘Global Defaults’  are called ‘Parent Profiles’. Parent Profiles can also have Sub-Profiles beneath them, and these work the same way, i.e. parent profile mappings carry through to sub-profiles, unless they are specifically overridden by a sub-profile.

If you have a lot of profile mappings that are similar, you can create a parent profile, and then use sub-profiles to define the exceptions.

Efficient usage of mouse memory via Sub-Profiles

If you are running low on memory you can use sub-profiles to make more efficient use of your Zs memory. As a sub-profile only needs to store the changes from its parent in memory. 

For example creating a general gaming parent profile with all of the Z's extra buttons mapped to numpad keys; then creating sub-profiles for specific games which add things like game specific tilt outputs or macros will save memory, even if you are technically increasing the total number of profiles loaded.

Without sub-profiles: Global + Desktop = 13% + ~3.6% per gaming profile.

Same setup using sub-profiles: Global + Desktop = 13% + ~1.8% per gaming profile.