It's pretty straightforward, but I think this is the information you are referring to:
Eheim Classic Canister Cleaning Instructions
Hope this link helps.
You may be over-analyzing it. My 2215 came with all the media and I just followed the instructions, not a problem. Of course, I'm one of the oddballs who reads instructions from start to finish before starting anything! I didn't cut my inflow/outflow hoses even since I wanted the canister at one end of my stand.
Good luck - I've enjoyed my Eheim.
I think these instructions are linked from another post on this site, I remember seeing it also, but could not find it!