Normally you only need to download the Windows version when installing the game for the first time. It's a bit more confusing at the moment due to the bugfix and the missing upload of the newest full version. I'm currently uploading the full version 18.12.16 for all platforms, then people can directly download those as usual.
In the image, the windows version is still older than the update files, so you could download the full version and then apply the update files to get to the newest version. The bugfix can be ignored as it is included in the update files (I deleted the download).
The version number is the date of the release in the year/month/day format.
Should you need help with using update files or moving save files when downloading the full game again, I made a video about both things here: