In the Nexternal platform, an Attribute is an aspect of a product that has multiple values from which a customer may select. For example, if a product is available in Red, Green, and Blue, then Color is an attribute of the product. If the product is further available in Small, Medium, and Large, then Size is also an attribute, and thus the product has 2 attributes.
An Option is a possible value of an attribute. In the above example, Red, Green, and Blue are options of the attribute Color, while Small, Medium, and Large are options of the attribute Size.
Attributes and options are set up on the product level. The following video shows you the basics.