zip file or WinZip > Extract for the others. In any case, right-click on the file to show the options, for example Extract for a. 7z files do need an outside tool such as WinZip.
zip file, you can extract it with Windows. (This is only true for skins within the same category, for example you can have a default skin that's only for females and one that's only for males, and they should both work.) You can have as many non-default skins as you If the skin is a.
Multiple default skins will conflict with each other, and only one will end up loading. One important note about custom skins is that you can have only one default skin per category of sim: it's the 'default,' as in, all sims get assigned it unless you choose something else. Here's a guide for setting up the Mods framework:
Sims3Pack file goes into Documents\Electronic Arts\The Sims 3\Downloads, and then you open the launcher's Downloads tab and install the skin from there. What you do next depends on the type of file you wind up with.
