In order to remove the promotional boxes from any template you would need to remove them from the template coding. To get to the HTML coding of your template please see the following video guide.
Each of the promotional boxes are elements. An element is inserted using the [ekm:element][/ekm:element] tag, a guide for this can be found here
The same applies if you are trying to remove any other elements from the templates such as best sellers or twitter boxes etc.
This is custom coding so if you aren't sure you would be best speaking with a designer or our own design team can make the changes for you but they are a paid service. If you would like to get a quote for any design changes please email firstname.lastname@example.org.