To install your sample pack - first do the following
1. Download your sample pack from your Downloads area
2. Double click to Extract the downloaded Zip file - this will reveal a folder containing your purchased samples as well as usually a readme file which explains how to make use of any EXS24 / Ableton Drum Rack extensions that come with the product.
3. You can then place this extracted folder into your usual samples folder - and access it from within your chosen DAW