I’ve been playing a long time so I don’t remember well what it’s like being a newbie and because I’ve been grandfathered past mist of the recent changes I haven’t seen them 1st hand, so I’ll give you what I can.
The last update changed game progression from “here’s a huge map with no direction on where to go or what to do” to “you start in this area, do some stuff, which opens up this new area, where you do some new things to open up another area, etc”. Completing challenges are what trigger these new areas.
That is outdated. You have to complete them to open new areas (kingdoms, game modes, the soulforge, etc). Challenges are a great help in getting resources - more so now than they were when I was a newbie.
Always a good idea to keep your hero in your attack teams if possible because there are a ton of classes that you can open up to change you’re hero to that give it different strengths. Each class needs to be leveled up to unlock those abilities & the only way to do that is to get xp from having that class activated while using the hero on your attack team. It will take a lot of grinding to get classes leveled. And leveling classes are required down the road for you to improve your kingdoms. Besides, your hero is typically stronger in stats than a lot of troops early on.
I can’t answer this because I don’t honestly know the order in which kingdom areas are opened to newbies. So I don’t know which troops of the 700+ you have available to you. What I will say is be frugal with your gold, souls & traitstones. Don’t just randomly start leveling & traiting any troop unless you intend to use them. It can be frustrating not having the correct traitstones available to trait a troop you desperately want to use. For a good while you will always feel you have a shortage of souls & traitstones & gold and a mountain of things to use them on.
But keep in mind there’s nothing I can think of that you can do terribly wrong at the beginning of the game that will just completely screw you over later on. So don’t be afraid to experiment a bit with traiting & leveling troops if they sound useful. They all need to be leveled & traited eventually, it just may slow you down a little if you trait the “wrong” troop.
That’s a great way to go about it! Something to keep in mind is that leveling a troop will make that troop stronger stat-wise (life armor magic attack) so they can last longer in a fight, do more damage, etc. Souls are much easier to come by in general than the correct traitstones to trait them so leveling troops you use is always good. Be more picky with which traits you give them. There are a lot if traits that aren’t as useful or aren’t necessary but by giving them, your team score increases which will increase the difficulty of some of the game modes you fight in like PvP.
Hope you continue enjoying the game and glad the guide was helpful! Our guys put a lot of work & thought into it but there is so much content that it’s really hard to boil it all down to a small list of best paths & practices.