A video covering the process of uploading products to a promotion throught he User Interface can be found below
Depending on the number of products being opted into a promotion, it is possible to add products through a CSV file generated from Seller Center.
1. Navigate to the promotion you would like to opt into and select "Add Products".
To add products in bulk, this is done by generating an export from the open promotion, this will ensure that only items eligible for that promotion are shown in the export.
2. Select Export> All Products
3. Once exported, the file will be found in System>File Manager
The file will display all items, it is recommended that all items that you DO NOT wish to be in the promotion are deleted from the export.
Once the finalized file is completed, ensure that the file is saved as a XLS.
4. Navigate to the Promotion> Import> Find File> Select Import
Once the products have been added to the promotion, they will appear within the applied promotion overview and have Pending status. Pending means the items are awaiting approvals, these approvals will generally occur within the last couple of days before a promotion is due to close.