Degas the gun fully, make sure you can push the bolt right forward.
Undo right side of grips, unplug Eyes and Solenoid
Remove grip frame and regulator (foregrip reg)
Look into the FRM and you will see an Allen Bolt, looks about 5 or 6 mm.
Undo this and pull it out, not losing the washer.
At this point, I would say it may be useful to have some spare cocker hose.
If the Karma comes with the nipple installed on it, great...if not you will have to remove the brass nipple from the Ego FRM.
It has a small hose on it which runs to the Solenoid Minifold.
You may be able to remove teh nipple with teh hose connected, if not...its pretty hard to pull teh hose off, so just cut it off teh nipple and replace teh hose.
So...use either new seals on top of the FRM or ones from old FRM , light smearing of oil and refit the new FRM with the bolt you took out, or use the one supplied if they supply one.
So now you should have gun body with noid hanging out and new FRM attached...install new hose between minifold and FRM or, if you took teh nipple out of your old FRM with hose still on, then you should have screwed it back in before mounting the new FRM, and its your own damn fault for not sussing that out.
Re assemble.
Gas up.
If you pulled the hose off the nipple and pushed it back on...expect a leak.
Job done.