Welcome RV! The Forum is pretty intuitive,
I’d suggest you click on the horizontal bars in the top right title bar, then drill down to a few topics that are of interest. You’ll also see “New” and “Unread”, which is where you can keep up with new topics as they come in.
To tag someone in a post, just put an @ in front of their name. Like this: @Retirementviewpoints. You’ll see their name pop up, just click on it and they’ll get notified.
Finally, if you want to respond to a specific statement from someone, just highlight the text and click the 'Quote box that pops up. It’ll include their sentence in your reply, and it’s a pretty cool feature.
Welcome aboard, hope the few tips help you learn your way around!