Processing addenda provides a number of challenges. This processing plan template for addenda includes prompts to consider at each necessary section.
Before beginning work on the processing plan, review the different models of processing addenda.
doing so, and determine which one most suits the collection you have. Questions to ask include:
What addenda am I processing? Has any of it been publicly listed (on OASIS)?
Has A/V been processed separately before? Will I add A/V to those collections or incorporate here? Have photographs already been cataloged? Has material in an existing finding aid been digitized and are there many digital objects linked in the finding aid?