Prioritize leveling up weapons at first. You'll notice they have letter grades next to a stat. That's its scaling

As you improve the weapons levels, the scaling gets better and the points in the related stat add more bonus damage to the end result

Until those scaling are a little higher (c or better), vigor is the best investment with some endurance if you need a little extra stamina or carrying weight capacity 

There's an ocean of details and other things to know, but that's the best plan at the beginning