After the plugin´s purchase you will get a link to the corresponding zip file to download.
Log into your admin account of your e-shop and search for Plugins tab in your left sidebar menu.
In the Plugins screen click on Add New button.
Then on Upload Plugin
A form for choose a file from your computer will be open. Click on Choosle File and select the downloaded zip file and upload it to your WordPress.
After the plugin´s installation you can find in installed plugins tab.
More plugins for WooCommerce from Toret