In a small business, some activities work thanks to a person's memory and experience. The problem arises when that person is absent: information, accesses, and relationships can become difficult to recover. Continuity requires recognizing these dependencies.
I propose that we start with activities that cannot be easily interrupted. For each, you need to know who performs it, what tools it uses, and what information it requires. It is not necessary to document each gesture with the same detail: priority depends on the consequences of absence.
A hypothetical example is the management of an urgent order. If only one person knows the correct contact and approval path, the entire service can slow down. Support and essential instructions allow a substitute to deal with the case, respecting roles and permissions.
The most useful test consists of a circumscribed test: can another person perform the activity with the available information? Difficulties show what is missing. The knowledge shift should be updated when changing tools and responsibilities. Making work transferable protects the enterprise and reduces the burden of those who must always be present to make everything work.