At this time strenee sims only uses .package files. They are hosted on www.streneesims.com for download and do not have to be unzipped.
Place the .package file in your Mods folder where the resource.cfg file is located:
Documents > Electronic Arts > The Sims 4 > Mods
**Note: You can add one level of subfolders in your Mods folder to help organize your files. For example:
Documents > Electronic Arts > The Sims 4 > Mods > Clothes
To add a new folder, right click in the Mods folder, hover over New and select New Folder. Name it whatever you like.
Further Documentation at Sims Wiki