The option Annotations From Subtraction... for multiple files is the same function as annotations from subtraction in the current open file (see the section called “Create annotation by subtraction” ), but applied to a selection of files. The first step allows to select a custom set of files in a file browser or to load a set of files that have been stored as a domain. For loading or creating new domain see the section called “How to select multiple files” The list of tiers is the sum of all tier names encountered in the selected files. The options in the next steps are the same, clicking the Finish button in the last step the new tier is created and populated with annotations in all files of the domain.