If you are interested in participating with any of the posted racing events, you may contact the listed event host.
The Touring Car Custom Track racing series is being hosted by RIP_DeadMansHand (PSN ID). You may send him a "Friend Request" via PSN. This event is held every Thursday Night @9pm in private lounges. This is a closed event and an invitation is required.
Or you can post a topic in the "Guest" section of the forum listing you PSN ID and you will be contacted via PSN. Also include the event that you're interested in and the event's host will contact you.