I dont get the hero thing

So i recently got the trio steam sale and started with Factions. I got to the second town and the game just shits on me, i cannot even complete the main story.

So i heard that this hero things help, but i dont understand them.

1- Do i need to pay extra 40 usd for 8 slots to have them? is this real?

2- I understand that u get them from nightfall, but i started Factions already. How do i get to LA from Factions to get some heroes? OR can i start ANOTHER character and do nightfall and i will have the heroes on my first character also?

3- My build is a disaster, i dont know how to pick and follow a build

should i refund?