How to add the Chrome Extension for the first time
The following steps are one time only, and are included in the installer
Opening Chrome's extensions page and turning Developer mode ON
Type chrome://extensions in Chrome's address bar and press Enter. Then switch ON Developer mode, in the top-right corner:

Click "Load unpacked"
A new row of buttons appears at the top once Developer mode is on:

Pick the extension's folder
In the window that opens, go to Downloads → VAN EXTENSIONS, click the extension's folder and press Select Folder:

Downloaded more than one extension? Repeat Load unpacked for each folder/extension.
Pin it to the toolbar
Click the puzzle piece next to the address bar, then the pin next to each VAN extension. The icon stays visible next to the address bar, always one click away

That's it. It will look for updates every 30 minutes
Manual updating later is one button: open VAN Chrome Extensions Installer and press Download again — same folder, and Chrome picks the new version up the next time it starts. Nothing to re-load, nothing to delete.