Thanks for writing in!
1.) The best you can do to learn more about the theme and its functions is to check out our knowledge base:
2.) If you want to remove or delete something, please make a screenshot and highlight or illustrate which one you want to do so that we will have some ideas of what you will do with your site.
3.) The huge text headings can be adjusted if you go to X > Launch > Options > Typography
4.) To have a fullwidth page and with no sidebar, you will have to set your global layout settings in X > Launch > Options > Layout & Design > Content Layout as "Content Left, Sidebar Right" or "Sidebar Left, Content Right" first so that the blog and the blog posts will have a sidebar. For fullwidth pages, you will have to change the page templates to Layout - Fullwidth or Blank Container page templates. To know more about page templates, please check this out:
5.) To know more about one page navigation layout, please check this out:
6.) We would be happy to assist you in anyways. Please provide the url of your site and we can change or guide you through the settings in the theme.
By the way, please understand that X theme is for beginners and intermediate users. Pro theme is more on for intermediate and advanced users like designers and developers.
Hope this helps.