You can access promotions using your Fixers login details at http://yoursubdomain.fixersworld.com/admin.
On the left hand side you can see the tab labelled 'Marketing'. If you click on this you can access your Promotions page.
Promotions can be set to discount prices by either a monetary amount or a percentage.
Promotions can also be set up to apply to specific products and to specific variants within that product on the right hand side.
Promotions need a start date and expiry date, the promotion will then start and end at midnight on the dates entered.