What's a good PvE build for me and my friend?
Well, “builds” are something that you really can’t optimize until you have full access to all of your trait points (i.e., level 80). At that point, builds will be more significant, not that trait allocation doesn’t matter at lower levels.
The advices I give to folks of any class they are new with is to spec first into toughness, vitality, and power, in that order. Toughness improves direct damage mitigation, vitality sustain damage (condition) mitigation, and power improves attack. The idea behind this is that taking care of defenses first gives you more breathing room with respect to learning about the class.
Especially if you’re new to the game, you should give yourself some leeway to learn how this game differs from others. Learning how to utilize dodges, evasive maneuvers, enemy cues, and how self-healing functions. As you get better, you might consider playing around more with power and precision for higher damage, or the warrior Discipline line.
As far as weapons go, the warrior can use more weapons than any other class, as well as use them in different combinations. Take the time to make use of different weapons and unlock all the skills associated with them (including underwater weapons). However, most warriors (and guardians and mesmers, actually) consider the greatsword to be their staple, if you will. It is a weapon that has a capacity for both high damage as well as high mobility, which is actually more significant than stationary defense in this game. Paired with that is typically a ranged weapon. Personally I favor the bow over the riffle as while it has a bit less range untraited, it has area of effect damage. It also contains the warrior’s only combo field, which is it’s burst skill, which can also serve as a teaching tool for how combo fields and finishers work, which is a game mechanic itself.
Those two weapons paired are probably the most versatile pairing warriors have, as they cover both melee and range damage, a stationary as well as movement skills, and combo fields (bow burst) and finishers (greatsword 3 and 4). In the long run, of course, I think it’s fair to say most warriors will always carry at least one of each weapon on them (two in the case of dual wielded weapons, namely swords, maces, and axes). For greater detail, there’s a warrior weapons guide on the top of this warrior forum section.
As far as armor goes, I’d say early on armor that focus on defensive traits, namely toughness and vitality. Early on you’ll only get one stat per armor, but eventually two, then three. If you start to feel more comfortable with your defenses, you can get armor that emphasizes power and or precision.
Utility skills are very versatile, and can really further the way your use your character. You’ll unlike them bit by bit, so when you do unlock one, be sure to try it out for a while. Utility skills like weapons and armor can be changed at any time out of combat, so feel free to experiment. Some very common choices, however, especially early on, are the shout “For Great Justice!,” the shout “Shake It Off!,” and Signet of Might, all in the first tier of utilities. Warriors have 4 kinds of utilities: banners, stances, shouts, and physical skills. It’s good to explore all of them.
Ultimately you’ll learn by doing more so than being told, but that should help get you started, I think. Make sure to always try a variety of things, and be willing to change.
If there are two of you, it would be a nice idea for one to run with warhorn and banners/shouts, offer some support.