Went to on line video and followed it. The old gasket came right out and the new one fit right in. Started at the top middle and worked the gasket in on both sides to make sure it was evenly spaced.
To perform the repair, the door panel must be removed (8 Torx screws) and the door removed from the hinges in order to access the lower door seal. For this model Bosch and other similar models, the hinge springs must then be disengaged (safer) or kept from retracting. To disengage the springs requires removing the entire unit, disconnecting the water supply, and flipping it on its side to disengage the springs. I chose the latter, keeping the unit in place, holding the hinges with vice-grips on either side, then removing the door. This was not easy and caution is required. Either method is risky with a 20-year dishwasher. The replacement part does not fit as well as the original (much sturdier) part, but appears to seal well for now. Repair videos on the internet are for different, newer models where disabling the hinges as described here is not required, making the repair much easier. Recommend looking carefully at your model/manual to determine if the difficulty of the repair is easy or hard.
There are two ways to do this repair: the "right" way and the hard way. I chose the hard way, as the right way involves disconnecting the dishwasher plumbing, removing the dishwasher from under the counter, taking all the outer panels off, and disabling the door springs. There are good YouTube videos on this. The hard way doesn't involve that -- but is not all that easy and I'm not sure I'd recommend it. The problem, in essence, is that to install the new seal there is now way to do it without taking the door off the machine and taking the door apart -- which requires that the springs be locked out, if not disabled.
I accomplished that part of it by opening the door, partially, undoing the two screws on each side which hold the hinges, taking the front panel off (piece of cake, with a Torx driver),slipping the door partly off the hinges, and then locking the hinges open with the pry bars.
There are an assortment of ways one could seriously damage either the door or one's self doing it that way -- the hinge springs are very powerful -- so I don't recommend my approach.