I just went through this last week with my first...
1. Acclimation
Floated the bag for 15 minutes to match temp, after the 15 minutes I added about 1/2 to 3/4 cup tank water to the bag every 5 minutes. Once the bag was almost full, dumped a little more than half out, place the bag back in the tank and continued adding water as described until filled again.
2. Quarantine
None
3. Handling
I usually wear gloves in the tank, so I slapped some on, gently scooped the nem out of the bag so the foot was on my fingers (palm up) and gently slid the nem in the area I wanted. It sat till for like a minute and found a spot an inch from where i placed it.
4. Powerheads/Pumps
Once I saw that the nem was settled in I turned on my PH to the lowest setting, which again caused the nem to move a little making itself even more comfy, Its been a week or so and has not moved since. i fed it krill for the first time last night and it enhaled it, so i think its happy.