A new window will open asking you for installation.
Open the folder where SIMS 2 is installed, there you will find the download folder, open it.
It will be downloaded in Zip format, extract it into any folder.
Download the MOD file from a genuine source.
If you want to make your SIMS 2 more intriguing here is the procedure to install mods on SIMS 2. There are mods available for character customization, cloths, map changes etc. SIMS 2 Mods enables the player to add various features to the game to make it more interesting.