Thanks for contacting us. Lets clarify a few things.
If you started to build your website using a different theme and still want to use the content of your old website you can find all your pages on WP Admin > Pages >
Note that pages built outside of Cornerstone cannot be edited with Cornerstone so if you find your pages via X > Launch > Content you might not be able to edit the content of these pages without erasing them, in that case I would reccomend you creating a new page to copy and paste the content from the original pages into Cornerstone pages or edit this pages in classic WP editor if you wish so.
Customizer manager is useful just if you have exported the customizer settings from another X Theme website.
X > Launch > Theme Options is where you set the general styling of your website simiarly to the customizer, but we recommend you using Theme Options on X instead of Customizer.
There you will set the footer, header, button styling among many options.
Your pages ideally should be edited with Cornerstone the X Theme Page Builder. I do reccomend you using the classic elements to start.
When you search the elements in Cornerstone you will notice there is Text and Classic Text. The Classic elements have less parameters and it is much easier for you to start with.
If you are finding content that you dont need what it is , I would suggest checking if you think you might use it or not and in case it is not necessary delete it so your backend is more organized.
If you have specific issues you are facing, plese let us know in a list like you did before and provide more detail about what you are trying to achieve,