I think I'm just confused about what it all means. Weapons either say STR E or D or something and I'm not sure what it means, even after reading tutorials.
right so, if a weapon needs a TON of STR and little Dex, its a STR weapon. And vice versa for Dex.
If it needs (by need I mean how much it needs to equip properly) both more or less equally, its a Quality build weapon (Curved Greatswords for example)
Then you have the scaling and STR weapons usually have better letter grading for STR and vice versa for Dex.
edit: actually more on this. open the inventory, notice how a weapon dmg will say like 150 + 40
150 is the base dmg. 40 is the Scaling dmg. so the weapon in theory will do 190 dmg. If you change the scaling, the base dmg will go down, but the scaling dmg will probably go up.
Lets say you change the scaling to STR (ashes of war change scalings btw). Now the dmg maybe becomes 140 base dmg + 55 scale dmg. So overall now it does 195 dmg, a little higher than before, and it will go higher the more STR you have (because that scale dmg goes up with more STR).