Depending on your browser you may need to save it to your computer first before running it. Below are some examples for different browsers.
Once it is downloaded, run/open the installer. If asked if you want to run the file, click Run.
Depending on your version of Windows you may be prompted to confirm that you want the installer run. Click Yes to continue with the installation.
Follow the prompts for the installer and it will install the appropriate version of the Banantag plugin on your computer.