I am using wpForo forum WordPress plugin. I want my logged in user to view a particular topic only. Such as suppose I have several school groups. Each student will be able to view the forums based on their selected school. I don't want to give them access to other topics. I have created school group for that, but that didn't help.
You should create forums for each school group, then set "Standard Access" to Usergroup whic is allowed to see that forum topics and set "No Access" to other Usergroups. Read this FAQ topic to understand forum - usergroup access settings: https://wpforo.com/community/faq/wordpress-user-roles-wpforo-usergroups-and-forum-accesses/