My themes page doesn't have an "add new" button
If you do not have an "Add New" button on your Themes page, you are likely using Wordpress.com.
Unfortunately, our themes are not compatible with Wordpress.com since Wordpress.com does not permit third-party themes to be uploaded (among many other limitations). Even with a domain or premium account, themes cannot be uploaded.
If you'd like to start a self-hosted Wordpress site, we have a step-by-step Getting Started Guide on our website.