You need to register to the site before posting, which takes only a minute, but you can view the forum and the posts without registering. Maybe your problem has already been answered previously.
You can post questions about submitting your creations, about creating tracks or cars, or just general questions about the site or suggestions for improvements.
The administrators try to read the forum daily or at least as often as their time permits.
Here is direct links to the sections to post to: