Supports are the additional build towers that help to, well, support your print and they are necessary to make certain prints exist -your can't just print in thin air! CraftWare has a great auto-support option, designed to provide a high and safe success rate of getting the object that you want in the end, but custom tinkering is always adviced to get into small areas and add a personal touch. Different mouse clicks and movements can be used to add and remove supports and variances can be made in the make of your supports by changing the characteristic settings in CraftWare. For limited interference to the print's surface, you must take the time to either build or modify custom supports that give a more "delicate" cradle; just beware that under support of your object, or weak support structures can lend way to a sagging print.
Please consult page 10 of the CraftWare User Manual for an in-depth explanation on how the whole support feature works.