These are sections for galleries. I would recommend to name the Container according to the number or like here with a clear description for easier recognition. You can change the content of the existing ones or you can add as many as you like.
What is essential: You need to give the Container not only a name you need to give it a unique ID. Click on the Conateiner and scroll down in the Inspector. The examples below have the ID "gallery-01“ or "gallery-02".
Via the ID you can address now your shortcode. The example below is: 

[[shortcode.galleries.gallery-01]]
„shortcode“ is required for the ShortCode component to recognize it. „Galleries“ that it is at the galleries page and „gallerie-01“ as the unique ID.