ArcGIS for Personal Use is not a downloadable "product" by itself, it is a licensing type. This means you simply need to download & install the products from the My ESRI site that you can access if logged in on the ESRI website after having bought the license, and in the case of ArcMap / ArcGIS for Desktop, separately authorize the software with instructions you should be getting from ESRI once you've completed the purchase and ESRI acknowledged that. For ArcGIS Pro, you do not need to authorize the software like with ArcMap, simply being logged in with the same account that was registered for your Personal Use license, should work. Pro will prompt you for that if you start it up.