Addon installation:

1. Download the addon following the provided url
2. Install and Activate WPC by following the instructions here
3. Go to Plugins > Add new in your WP-admin website
4. Click on Upload Plugin then click on Browse... and select the file you've just downloaded
5. After the plugin has been installed, click on Activate

To activate the addon on a specific calculator:

1. Click on "WooCommerce" > "WooPrice Calculator"
2. Click on the "Calculator" tab
3. Click on the dropdown menu of your calculator and click on "Table Addon"
4. Click on "Activate" to enabled the addon