Do you know if it's possible to add the shoes and parts of outfits in the programm, to be able to use them as normal clothes for making my own characters ?
Yes, it is. You'll need the
moreClothing mod created by
@sby. It can be somewhat tricky to setup if you're new to SDT modding, so we encourage new users to download the
sby Loader Pack instead.
moreClothing allows you to add new items to the clothing selectors (the UI elements with the ◄ ► buttons). The items added
can be standalone mods (such as a pair of shoes), but they can
also be complex costumes (or entire suits of clothing). moreClothing allows you to chop up a SWF file and then mix-and-match the pieces with other SWF elements.
Or could we only use them downloading them entirely ?
For now, you should
go ahead and download any mods which catch your eye. You'll be able to use many of them via
moreClothing. A few will prove incompatible (because they're
Loader mods), but you can still load them manually or incorporate them into Character Folders.
By the way - you can read about Character Folders (and a few other important topics) in the
Newbie Guide.