How can I add banners?
There are no special instructions for this. Adding banners is the normal procedure for OpenCart. Proceed as usual. Banner images are placed next to each other automatically. All you need to do is follow the optimized banner sizes which is mentioned in the installation guide.
However, here is a tutorial on how to add banners: http://youtu.be/oycJ54cR7lU
or here: http://www.support.mywork.com.au/opencart-15-banners-module