The answer is nearly the same as for your similar question (https://www.researchgate.net/post/How_do_I_see_my_papers_on_researchgate). Currently, no research items in your profile are classified as books. However, when ResearchGate algorithms import data from other platforms, sometimes books are classified wrongly as articles. In such cases, you may change the type to book, see "How do I edit my research item's details?" in https://help.researchgate.net/hc/en-us/articles/14293081125777-Reviewing-editing-and-featuring-your-research for instructions.