A good seal pick is a necessity in any mechanics tool box.
Make sure the area is clean. Wipe clean with a cloth rag, try not to shove any material into the area. Carefully use the seal pick to remove the old O ring.
Clean the area again with a cloth rag, you can use some lectra motive contact cleaner on the rag, do not spray onto kick shaft, you will flush debris into the bushing. However, you can put a rag on the shaft and cover the case, and use the contact cleaner to clean up the splines on the kick shaft.
While you're at it, clean out the mounting bolt hole and threads.
Put a little grease on the shaft and O ring and slide it into postion. You will probably need to use a thin blunt object, like a small flat blade screw driver, to push the O ring into the case recess.
Clean the shaft up good with a rag. Put the thinnest of coatings of never siese on the splines of the shaft and mount the kicker.
Be sure you have cleaned up the mounting bolt, and put a dab of red loctite on the the bolt threads, and tighten to specified torque.
You're done.