To start using the theme, generally you will only need to follow these 3 steps.
Be sure to install this plugin on your site: https://downloads.wordpress.org/plugin/video-thumbnails.2.12.3.zip
Fill in your Amazon API key from Settings -> VidiZon PRO Amazon settings menu.
Go to add Post -> Add New. And you can search for Youtube videos and insert Amazon product into your post using the button provided on the post editor: https://prnt.sc/ju2no8
Then add some content on the post (can be quick description about the product, your point of view about the product, etc).