Just got Blightheart the soulbound arquebus. 

Requires 30 dexterity afflictions to level up. How do i do dexterity afflictions on my pure ranged ranger?????

I dont understand

Hobbled, Immobilized and Paralyzed are dexterity afflictions. Use abilities that inflict one of these, like Hobbling Shot or Binding Roots for example.

Oh ok, thanks

And you don't have to apply them with the gun. You just have to hold it in your hands while casting a spell like Binding Web for example. If you hit several enemies then all hits count. Since Binding Web reapplies "immobilized" in pulses you might hit 30 appliances after one single cast.