Congratulations on purchasing a Frooition Bigcommerce design! You will now be prompted to download the .zip file containing all of the files needed to apply the design to your website.
Once you have saved this .zip file to a secure location you will need to log in to Bigcommerce. Once here, navigate to Storefront, My Themes. There is an 'Upload Theme' button to the right of this page:
Click this and follow the instructions in the pop up window, either drag the .zip file into this window or select it using the blue button:
When you have completed these steps the theme will appear in the My Themes section of your BigCommerce dashboard.
This gif will run through the steps required: