Congratulations on working with one of your favorite brands! If you promised to deliver content to the brand as part of your product request, it may be confusing on how to submit that content to them.
The best option is to reach out to the brand via email. In the emails sent about your Product Request, the brand's email was listed so that you could reach out if needed. Using a file sharing service like WeTransfer, Dropbox, or Google Drive shared folders are easy ways to share the images or videos with that brand. Shoot them a quick email asking them how they'd like you to share your content with them!