Yeah it's going to be a free to play game that is currently in open beta. I play once in a while. This reddit thread is a really good starting guide. It includes a deck list for each class that uses all free cards if your completely lost when it comes to deck building. I think the most important concepts starting out are card advantage, board control, and using health as a resource. Basically you always want to maximize the value you get out of each card; do as much damage or clear as many opponent cards while using the fewest cards possible. Also unless you are literally going to die next turn, health isn't a big deal. Having strong minions on the board or a stacked hand is much more important that having more health at almost any given point in time.