You have an option called “Show Content in Archive Pages” at the very end of General tab of theme options which lets you do that. Unless you use a WP more tag, the content will show up on the blog page.
As far as the image goes, at present the theme assumes that the main image will be on the top and that will be featured image/video/slider. You would not need to insert this image/slider/video into the post content since it will show up both in single post as well in the blog page. If you need to disable that and use the ones in the content only, let me know and I can suggest something that you can do through CSS. Thanks