Sometimes you may want to change some attribute for a number of items at once. Instead of opening each individual item for editing, you may use the mass update function for that.
To mass-update some items, do the following:
Replace applications will remove the item from any existing applications and replace those with the one(s) specified in this field.
Add new or existing applications allows to specify additional applications from the existing ones or enter completely new applications for the items.
Both these fields are auto-complete - starting to type in them offers a dropdown of matching applications. If the application is new, it also appears in the dropdown and it is indicated by (new) after the string. Just scroll down to select.