If your succession plan calls for employees to buy your business and take over running it, at some point you have to figure out what training they will need. The fancy word for this type of thing is skills gap. What skills will the new owners need and what skills do they currently possess? The difference is a skills gap.
The first step is for you to figure out what skills are needed to run the business. These are skills that you have or that others in your organization have, and you rely on them. The next step is to see which skills are leaving with you. Certainly your skills are leaving the organization, is there anyone who is going with you? Your spouse perhaps?
The next step is to make a list of the missing skills and figure out if the training will happen on the job. Or is there a course the new owners should be taking?
Either way, you need a plan.