Yes, you are reading well, it downloads ALL the articles from Wikipedia and creates an offline wikipedia in your computer. Choose the language you want to download and prepare your HD, because it weights a lot: English version: 5585 MB; French version: 1360 MB; German version: 1779 MB or Spanish version 850 MB.
The progress bar indicates the download status of the corpus of your new encyclopedia.
Kiwix is the application that will allow us to check the content of the Wikipedia offline, exactly as if you were surfing the web, it also includes some other featuress such as advanced search or search history.
You can download more than one language version at the same time, the limit is your HD free space.