After you have logged in and you have valid purchase you just need to click on the support in the main menu :
Now you need to click on Submit a request:
After that, you just need to complete required field and submit the ticket. If you wish to have quicker support also provide Your site URL, username and password. If you have purchase theme via Themeforest also provide us the license code. It’s also very helpful if you attach some screenshot of your problem.