This plugin is properly installed. Groups are added, with people in them. However, when you try to add any posts there are no buttons to create topics or posts. I looked over the forums and the plugin author's website. This issue was never dealt with in the WP support. You could sign up for pay-for-support at the author's website.
I have figured out how this plugin is supposed to work, which is important if you are not a programmer (I am not).
The problem is that the INSTRUCTIONS are not clear. If you follow the instructions and stop there, you are screwed. I didn't watch the video, so I don't know what it says. I believe written instructions should be complete.
1. You MUST set up categories AND under those add the actual forums from the administration panel. There is no provision for users to add tiers, only topics.
2. There must be three tiers with the last one leading to the "start new topic" or "subscribe". You can't stop at putting in your categories.
It will look like this: Forum » Equipment and Tools » Man Power Tools
This is how it is done:
1. After installing and activating; click "forum structure", "add new"
2. After typing the information about your category, click "save category",
3. Now you are at the category list page. Create all the categories you wish.
4. Choose a category to work with and click "add forum" on the right side of the screen.
5. After entering the desired information about the forum, click save forum.
That concludes the forum part, for now. You will be back.
To configure users:
1. Click "user groups" and then "add new". Create the groups you wish.
2. Click "add members" and begin adding members from your registered users list. Type each user name and separate them by commas like this: mary, mandy, james, truckman
3. Only users added to the group will have access to the forums you check. When you are finished adding users, click "add users" under the text box where you added the names.
Ok, you are NOT done yet.
Go back to "forum structure" and find the word "modify" next to a category. There is a list of user groups you created earlier with a check box next to each one. Click each box for the user groups you want to have access to the category. Click "save category".
Now your forums should work correctly.