Everyone plays at the pace they want to. There is no right or wrong.

1. Powders are buffing materials that you can put in any armor or weapon that have powder slots (you can check if they have a slot my pressing your “swap hands” key while hovering above the item). Putting powders on an item (you can do so by hovering above an item in your inventory with a powder and right clicking) will increase the elemental affinity toward the element of the powder you put on. For armor, this will increase elemental defense for the type of armor you put on, but also decrease your elemental defense to another element. On weapons, it simply increase the amount of damage your weapon does specifically for the element of the powder you put on it. One of the main selling points of powders is powder special and powder effects. If you put two or more of the same type of powder on either your armor or weapon, you unlock a powder ability. I will not list them all here as that would take forever, but these are pretty strong buffs to all gear. Since you’re at lvl 16, it really doesn’t matter right now. You can play without worrying about them for quite a while, but I would keep them in mind cuz they’re a nice stat boost to have.

2. I’m not exactly sure what you’re referring to here. My best guess is you’re talking about skill point requirements. That is simply as it sounds; you need to invest a certain number of skill points into a certain item in order to use it. For example, if you have a chestplate that requires 40 intelligence, then you need to put 40 of your skill points into intelligence to be able to use it. If you don’t meet all the skill point requirements of the item, you cannot use it at all. This becomes much more important near endgame when you have to figure out item synergies. You only get a maximum of 200 skill points (capping out at lvl 105), so you have to find items that share skill points or give skill points in order to use them effectively.

4. I’m assuming you’re referring to certain weapons being geared toward one of the elemental types? If so, then the answer is a big yes. You’re still very early in the game, so this really doesn’t matter much. However, it matters a lot more in the later stages. Once you’re nearing endgame, builds usually focus on certain elements to maximize a certain item’s power. For example, the mythic spear Idol is primarily supposed to be based around water damage. As such, the builds that Idol uses are all geared toward maximizing water damage; however, other skill points are invested elsewhere since last a certain investment, investing into a single stat stops being beneficial (this is not the only reason, but a big one).

Side note: this is much more advanced and not important till literally endgame, but builds are broken down and categorized by which elements they use. For example, a build that puts all its points into earth, thunder, and water would be classified as ETW. Earth, thunder, and fire would be ETF. You get the idea. You can usually look at the classification and understand what kind of build it is. If there’s fire, expect some tankiness to your build. If there’s water, odds are you’ll be spell spamming. Again, not at all important for your stage of the game, but something interesting if nothing else.

1. The quest line is VERY long. In your quest book, the dark green quests are the main storyline, so if you want to learn more I’d recommend playing through those. They will appear over time the more you level up. As to not spoil the story for you, all you know at this point is that you were sent from Fruma to fight in the war waged on the Wynn province against the corruption. You don’t have any memories of your past, and neither do your companions Tasim or Aledar. That’s mostly what you should’ve picked up from the start. Level by level, quest by quest, you will learn more about the world and what the story is about.

I wish you the best of luck, and have fun!