There are card now that have text that say "Enhanced unit gains edge 2" or While you control more Hoth Objectives then your opponent, each of your Speeder units gain Edge (1)". I am very confused by what this means. I get how edge battles work but does this text mean force icons are added or what? Can someone please help. Thank you.

Edge(X) means that when that unit is participating in an edge battle, it contributes (X) force icons to your side. For instance, Mon Mothma from the Core Set has Edge(1). Whenever you would use her in an engagement, you already have 1 force icon to your side.

To further back this up, here'e the rulebook entry on the Edge(X) Keyword:

The "Edge" keyword is always followed by a value. This value is the number of additional force icons the card's controller counts in an edge battle resolved during an engagement in which the card with the "Edge" keyword participates.

Does edge (x) stack? So if you have 3 units, each with edge (1). Do you add 3 to the edge battle due to three edge(1)s?

Does edge (x) stack? So if you have 3 units, each with edge (1). Do you add 3 to the edge battle due to three edge(1)s?

Yes. Also, if a unit gains edge (x) from multiple sources that also stacks. For instance, if you have a Fighter with Precision Flying and Soontir Fel on the board piloting, the fighter would gain edge (2) and edge (1) and function as if it had edge (3).