Sims3pack format
Install the sims3pack by double clicking on it after extracting. The launcher will open and the file will install automatically. If you want to install more files at a time place the sims3packs in this location: My Documents > Electronic Arts > The Sims 3 > Downloads folder Then open the launcher, click on the Downloads tab, select the files that aren t installed in the game and click install.
You can also use 3viewer to batch install more files at a time.
.package format:
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.
Or
- You can install them manually:
*You will need a file called Resource.cfg, which you can download here.
*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 Program Files > Electronic Arts > The Sims 3 > Mods > Packages.
For more detailed instructions please visit Sims3Wiki.
For more info about WinRar go here. You can use any other program that handles rars, a free one is 7Zip.