Assuming you are a member of a private group, you can post a new topic to that group, by navigating to the topic category for that group and then using the New Topic button to post to that group. When choosing the category for your topic, please be sure to choose the private category, you want to post to. If a category is private, it will have a small lock next to the category.
Remember to be sure you are posting to the private category. If you choose a public category, your post will be public!
