First thing first. You must have an account with ThemeHunt. After successfully creating the account, login to the marketplace.
You will see the 'OPEN A SHOP' link on the top menu bar.
Click the 'OPEN A SHOP' link. You will be taken to the shop landing page.
Scrolling down, you'll get the 'Upload Now' button.
Clicking the 'Upload Now' button brings the item upload/submission page. If you are not already logged in to your ThemeHunt account, you will get a login page. After logging in, you will be redirected to the item upload/submission page. Please check the following screenshot to have a look at the theme upload/submission page.
Don’t forget to read the submission guidelines to ensure that you are aware of the standard practices on the marketplace