This is the process for my 4010 with the 60" MMM. I hope it helps.
Remove the pins from the shaft that hold the 3PH lift arms on, and remove the spacers between the lift arms and the pins (Hopefully there are spacers). There are 2 brackets that are "L" shaped; approx. 6" long, 5 inches high, and the "L" is about 2" long. These fit on the shaft in place of the spacers, with the "L" portion of the bracket sitting on top of the lift arms - when the arms go up they push up on the "L" rotating the bracket around the lift arm shaft.
There are 2 "turn buckles" (my term, not necessarily the manuals) that attach to the "L bracket" and the rear of the "mower lift arms". The turnbuckles have a slot on one end. The slot end attaches to the "L bracket"; this slot allows the mower to float.
The other end of the mower lift arms attach to brackets that attach to the outside of the frame. There should be 2 pcs. of plate steel that need to go between the frame and these brackets (1 pc. per bracket) that are used if you do not have a FEL.
Make sure the 3PH is lowered at this point.
In the approx. middle of the lift arms there is a hole for the pin that lifts the mower. Line up the hole with the U shaped mower mounting bracket and put the pin in...same thing both sides.
Front frame mount: Bolt into place between the frame rails at the front of the tractor. Attach front lift arms of Front lift assembly to the mower and insert the spring loaded "J" hooks thru the hole in the front mounted lift arms. Install Front lift assy. into the Front Frame mount, lift the arm on the Front lift assy. rotating it until the pin in the assy. can engage into the hole in the mount.
On the end of the mower drive shaft, push the collar back and rotate it; it will lock in place. Install onto PTO shaft until collar releases and locks into place.
VIOLA ! Raedy to mow.
BTW...before installing your mower, I would suggest making sure the bolt that holds the drive pulley onto the gear box shaft is tight. Mine wasn't and allowed the pulley to loosen on the shaft, which broke the bolt. At this point, you pull the mower back off, take the drive unit off, try to find a metric bolt (M10 X 1.5 I believe) at night or on a Sunday (cause that's when it ALWAYS happens). Put it back together, put the mower back on and try again.
This is all from memory so forgive me if I left something out. Forward any questions and I'll try and answer them.
Tip: turn 2 rear wheels 90 degrees to normal orientation; remove spring from front right wheel and turn the wheel 90 degrees also. This allows the mower to "roll" under the tractor.
Good Luck!