Hello @nicole79,
Yes! Just like Katerina said, Private Messaging is possible here in the forum. Let me know if you were able to send a message or if you still need help! 
My personal favorite “walk through” of the site is the discobot tutorial- discobot is a cute little forum robot who can show you the basic tools of the site.
Here is how you can connect with discobot and go through the tutorial:
—> Start the Interactive Forum Tutorial with Discobot!
We have many helpful guides here in the forum to walk new users through different features! Feel free to take a look at this masterpost that houses all of the features and how to use them.
→ Forum How-To 
Guides for Using the Forum!
If you’ve double-checked your membership and it is definitely active (as only active members are able to reply to posts), then perhaps you have found some old discussions?
While the majority of discussions here in the forum are open for interacting with, you may come across old discussions that are closed. These are marked with a padlock (
) and can no longer be replied to.
However, if there is a post in a closed discussion you’d like to discuss further, it is possible to send that user a PM or to reply in a new topic (check out the forum guides linked above for how to do those things!)
Please feel free to reach out if you are still experiencing troubles or have any more questions!
Blessed be 