Create a txt document with your Web.config settings.
Below is an example that shows a minimal Web.config file
<?xml version="1.0" encoding="utf-8" ?>
Save the txt file as Web.config.txt.
Upload the file to the root directory (web/content/) of your windows hosting package.
Rename your Web.config.txt file to Web.config by removing the .txt extension." This can be done using your FTP client
You have now added your Web.config file.