If you want your site like our demo, theme comes with demo installation please check the documentation for demo installation. It will create posts on your site. you can edit existing post as your wish from WordPress Admin > Posts > All Post.
please check the article. it will help you to create new post from WordPress Dashboard: Post Article
I am quite new to web design and need some help.
I created a blog bage and added to the menu.
But I dont know how to make posts appear in the blog menu.
Could you please write an instruction how to set up the blog ?
I would like blog structure to be just like on your site.