Basically, just a template of where morphemes go in the verb complex, like
Past Prefix | Agent Agreement Marker | Aspect Prefix | {Tense Stem} | Modal Suffix | Patient Agreement Marker |
It's kind of good way to get an overview of what things might be marked on the verb. Obviously, it's more helpful for language which are polysynthetic, where there are a dozen morphemes that can go into a verb.