Though this guide is still relevant, some users have reported problems using it. A new guide is now available at http://www.modthesims3.org/downloadcenter/content/how-install-mods
Using TS3 Packages
Custom content for The Sims 3, like The Sims 2, is generally in .package format. But you can't just put them in your My Documents\Electronic Arts\The Sims 3\Downloads folder - that doesn't work! You will have to get a special file to enable the game reading custom content, and put the content in a special place.
Summary
* You will need a file called Resource.cfg, which you can download by clicking
http://chii.modthesims.info/getfile.php?file=927170.
* Extract the Resource.cfg file from the RAR.
* Windows: Place that file in Program Files\Electronic Arts\The Sims 3\ - then place any .package files in Program Files\Electronic Arts\The Sims 3\Mods\Packages
* Macintosh: Place that file in The Sims 3.app > Contents > Resources > transgaming > c_drive > Program Files > Electronic Arts > The Sims 3. Then place any .package files in The Sims 3.app > Contents > Resources > transgaming > c_drive > Program Files > Electronic Arts > The Sims 3 > Mods > Packages
Detailed Instructions
Don't understand based on the summary? Here's the "for dummies" steps:
Step 1 - Get a RAR Extractor
First, you will need a program that can extract from both ZIP and RAR files.
Windows
We recommend 7-zip, which is "Free". That means that you can use it for free.
Macintosh
On the Macintosh, the free utilities StuffIt Expander and The Unarchiver handle most any archive type created on a PC.
Then, once your preferred de-archiving application is installed...
Step 2 - Get Resource.cfg
You will need a CFG file with certain contents, to tell the game to read files in a specific directory.
The easiest way to get that CFG file is just to download a ready-made one.
* Download a Resource.cfg file from MTS. To download this file, you must be logged into ModTheSims. Login here or register here.
* Save that file to somewhere you can locate it easily - your computer's Desktop is the easiest.
Step 3 - Extract Resource.cfg
Once the file has finished downloading...
* Go to where you saved it (like your computer's Desktop).
Windows
If you got WinRAR, you should be able to just right-click on the file and choose Extract Here. Then you should have a new file below the RAR, called Resource.cfg (or maybe just Resource, if you aren't viewing file extensions).
[edit]
Macintosh
On the Macintosh, double-clicking on an archive will extract its contents in the same location.
Step 4 - Place Resource.cfg
Windows
* Right-click on the Resource.cfg file on your Desktop and choose Cut.
* Then click on Start - My Computer.
* Navigate to C:\Program Files\Electronic Arts\The Sims 3 This is the main folder for The Sims 3, called the "root folder"
* Right-click in an empty space in the root folder and choose Paste. The Resource.cfg file should appear there.
Now your game will recognize content if you put it in a specific folder, defined in that file you just placed.
Macintosh
In the Macintosh version, this hierarchy is hidden within the Sims 3 application. To get there, follow these steps:
* Right-click (or Ctrl-click) on The Sims 3.app.
* Choose "Show Package Content" from the contextual menu.
* Navigate through: Contents > Resources > transgaming > c_drive > Program Files > Electronic Arts > The Sims 3. You are now at what is referred to above as "the Sims 3 root folder".
* Paste the Resource.cfg file into this folder.
* Make a backup of your new folders since when the inevitable patches and updates come out, if the application is replaced in its entirety your mods will be overwritten.
Now your game will recognize content if you put it in a specific folder, defined in that file you just placed.
Step 5 - Download/Extract Custom Content
Now you're ready to download the content you want.
* You should already know how to do that - click the link to get the ZIP or RAR file and save it somewhere you can find easily.
* Then extract from the ZIP or RAR file to get at the .package files (Windows: right-click, Extract Here; Macintosh: double-click.).
* If you happen to download a SIMS3PACK file, just double-click it and the launcher will put it where it needs to go.
Step 6 - Place Package Files
For PACKAGE files, you need to put those in a specific folder yourself.
Windows
* Select the .package file(s) after extracting. Right-click and choose Cut.
* Then click on Start - My Computer. Navigate to C:\Program Files\Electronic Arts\The Sims 3\ - the Sims 3 root folder.
* Right-click in an empty space in that folder, and create a New Folder. Name this folder Mods and then open it. You're now in C:\Program Files\Electronic Arts\The Sims 3\Mods
* Right-click in an empty space in this folder, and again, create a New Folder. Name this folder Packages and then open it. You're now in C:\Program Files\Electronic Arts\The Sims 3\Mods\Packages. This is the folder where you will place the package files.
* Right-click in an empty space in this folder and choose Paste to paste the file(s) that you cut after extracting. You should see the file(s) appear.
Macintosh
In the Macintosh version, this hierarchy is hidden within the Sims 3 application. To get there, follow these steps:
* Right-click (or Ctrl-click) on The Sims 3.app.
* Choose "Show Package Content" from the contextual menu.
* Navigate through: Contents > Resources > transgaming > c_drive > Program Files > Electronic Arts > The Sims 3. You are now at what is referred to above as "the Sims 3 root folder".
* Create a folder called Mods. Double-click on it to enter the folder.
* Create a folder inside Mods called Packages.
* Paste any .package files in this folder to install them to your game.
* Make a backup of your new folders since when the inevitable patches and updates come out, if the application is replaced in its entirety your mods will be overwritten.
Step 7 - Play!
Hopefully, the above steps should have worked just fine, and you can go ahead and play with your new custom content in-game!
If it didn't work...
* Did you place the Resource.cfg file where you were supposed to? See Step 4 for where they go.
* Are you trying to put the files in My Documents\Electronic Arts\The Sims 3\Downloads? They don't work there! See Step 6 for where you're supposed to put them.
* Are you sure you're looking in the right place? Check back with the creator to make sure you know where the content is supposed to show up in-game.
credits
http://www.modthesims.info/wiki.php?title=Sims_3:Installing_Package_Files
