It’s pretty easy first step play through the mission ‘Voids Edge’ until you get to the final boss, once you get there take the boss down to about 50% health.
Go stand at the back where you can buy drone and when the weaker Varelsi come get a few body shots (one headshot kills them so avoid those) then use Claw Lunge.
Hopefully this helps 
Cool video but honestly the easiest way for me is to do The Archive until you get to the Minion Data Escort part (probably 10 mins into the mission) (the little dudes trying to walk to the sentry) and you can farm Varelsi that perma-spawn under the bridge (As a bonus you can kill the Varelsi on the way with Claw Lunge as well). Just ignore the Thrall/Jennerit spike spawns and let them kill your escort minions so the story wont advance.