Users are required to be TL2 - Member or above to post in the Live > Events category which is where you can advertise and publish your event topic. Taking a look at your profile, you are currently TL1 - Basic Member. To reach TL2, just keep being active and contributing to the forum in a positive, respectful and productive manner and you’ll reach TL2 at no time.
Feel free to take a read of the two topics linked below for more information:
Let us know if you have any questions at all. Take care!