If you want to install item in type
" .sim3pack " you need to bring your file
to place in folder Documents\Electronic Arts\The Sims 3\Downloads
but you can't create subfolders for separate the items by categories
then you must run the game with "Sims3LauncherW" (in the pic below)
(ขออนุญาตขโมยรูปหน่อยนะฮะพี่เรด)
do u c the icon name "..Sims3LauncherW.." ? run it
go to download tab select the items you want to install then press the install tab below wait until install success
it will show details what items you've installed

(ขออนุญาตขโมยรูปจากกระทู้คุณ vchukkrit ><)
i've problem some item be installed be in the game but it not show Installed Icon
ok then let's start how to install item type "
.package" ...... as mrred said
you want Mods folder to place in Documents\Electronic Arts\The Sims 3
in "Mods" folder has folder name "Packages" ..item type .package must be in Packages folder (as their name

)
you can create subfolders in "Packages"folder for separate the items by categories
such as hair, accessory, cloth, pose, build, buy etc.
and you can subfolder in subfolder in subfolder lol for easy to find when you have something to do with it
the items type package may be causing problems with your game when something goes wrong -o-
u can check it by program
Sims3dashboard if all of this can't help you a bit ..i'll cry

LOL

let's enjoy The Sims 3