This is a good question. The help pages do not give any definitions for the various types of "research items". Particularly, I do not understand the difference between "Conference Paper" and "Presentation". I guess they mean oral presentations at a conference or elsewhere (not at a conference). Bibliographically, all three types are similar or even identical, but the original forms of these presentations (as poster at a conference or orally at a conference or orally elsewhere) differed.
Some authors use the type "Conference paper" for the published version of their presentation, see, e.g., https://www.researchgate.net/publication/374429558. However, I myself use "Chapter" in such cases, because this allows to indicate the title of the proceedings and the publisher.