New Player Tips and Invite Code
There really isn't much in the way of a walkthough for this game since it is pretty much the same progression from location to location but with an increasing level of difficulty and number of waves you have to complete in order to clear an adventure. It isn't D&D in the roleplaying sense but it is a pretty fun game and can be played well by non-shop players which is better than a lot of Free to Play apps out there.
First, I would suggest when starting out the game to utilize the special events that happen weekly in order to get a large number of chests. The more chests, the more chances to gain Rare or better cards. The faster you build up a base of rare or better cards the easier it is to adventure.
Some strategies I can provide is to manage your energy well when in the starting levels of the game. That means use all your available classes so that you can save enough energy at the end to level up one of your characters and refresh you energy back to 100. Also focus on leveling up the base classes that open up the tier 2 classes to increase the amount of time this strategy will work. Effectively managing this flow will allow you to basically play indefinitely at lower levels. This allows you to both increase the levels of all your classes but also give you much needed chests to get rarer cards.
Another suggestion is to get in a good party of players who have 1000+ Attack/HP points so you can avoid the hassle and time of getting lower point help when you adventure. Also if you haven't already done so you should use an invite code in order to get a free Rare quality card and potions.
Feel free to use my friend invite code of sLMj6g and my party's name is Legion if you want to join.