How do I post pictures of blog posts?

Before opening the post I want you to show the main images of my pots on the page of my blog. How do I do?
I would also like to add the same search fields, recent posts and calendar.
I want to leave it this way: http://demo.athemes.com/sydney/my-blog/
My site is like this: http://teste.lucassousa.me/blog/

Hello there,

To display the sidebar widgets, from your site dashboard (/wp-admin), go to Appearance > Widgets, drag-drop desired widgets in the list of available widgets to Sidebar box.

To set the featured image of your post, go to Posts menu. Edit your post item and upload your image to the Featured Image box located at the most bottom right.

Regards,
Kharis