I would point out that some of the torque values above are different than what is in the Shimano Dealer's manual:
https://si.shimano.com/pdfs/dm/DM-FC0002-12-ENG.pdf
Use instructions to properly install your BB.
To preload the bearings, Timothy had it right: Snug up the NDS arm using the tool and your fingers. Then push down the (useless, IMHO) little plastic thingie, and then tighten the crank arm crank bolts to 12-14 Nm. As suggested above, you do this by alternately tightening each of the two opposing crank arm bolts in turn, working up to 12-14 Nm. I believe that this is 106 to 124 inch pounds.