Admins can have their own skins
Public players can have their own skins
Skins are stored in the player settings and can be modified by using the settings command
Miscallenous skins can be specified that can be used with ma_setskin to affect players.
Skins can be forced as default skins for public players.
Optional autodownload to client functionality.
With the mani_skins_force_choose_on_join you can force the settings or skin chooser menu to appear on team join.
The skins folder is under $BASE/cstrike/cfg/mani_admin_plugin/
This folder holds 7 files: -
admin_ct.txt
admin_t.txt
public_ct.txt
public_t.txt
misc.txt
reserved_ct.txt
reserved_t.txt
These files holds the menu name for your skin and the config filename that holds the resource filenames (.mdl, .vtf, etc)
The examples provided are commented out.
There are 7 folders relating to the different catagories. In these folders are the files specified above.
Each file must contain the resource filenames needed for a model.
If you are after skin packs you can see L Dukes web page at www.lduke.com/plugins/modelchanger.php for packs
There is also an extremely good guide there on how to compile models with new skins.
I should also point out that the models are quite large so keep this in mind because your players will be forced to download them. You should only consider it if you are using sv_downloadurl as it takes aaagggesss by trickle download from the server. Don't forget the 56kers too.
If you want a skin to override the defaults, add a directory in the /skins/maps/ directory that represents the map you want to use. Within that directort replicate the stucture that is used in the default /skins directory
If I wanted special skins for de_dust I would add a new directory called de_dust in the skins/maps/ directory
/mani_admin_plugin/skins/maps/de_dust/
within that directory would be the usual layout of skins to be used.