Every skate blade has an inside and outside edge and a groove between the edges, called the flat of the blade. The sole function of the flat of the blade is to glide straight forward and straight backward. You will be gliding equally on both edges and in a straight line.
Edges have multiple functions.
Blade edges are designed to cut into the ice. The pushing skate is the one that must grip the ice to set up a powerful push. These two functions are totally separate and distinct from one another. One skate digs in to push while the other digs in to travel a curve or circle. Before making the edges work to your best advantage you must first know what is, and then how to get onto, a functional edge.