Drupal 8 file structure?

Question

CMS

Recently I got a task to create a site on Drupal 8.
I installed everything fine, set up the database.
Tell me about the structure of the files on FTP, what lies where?
I’m sitting for the second day and I can’t understand anything (before that I worked with Drupal 7).
If on Drupal 7 I rolled the desired theme and drove it ( page.tpl.php/connection.php/template.php ) and so on.
On Drupal 8, nothing is clear at all ... As I understand it, everything is driven into the core there.
Maybe I'm confusing something.
Thanks

Answer 1

The core folder contains the Drupal core, which I do not advise you to touch. You can put all your custom themes in the modules folder, and themes in themes. Those. except that the core has moved to core, the folder structure is almost the same as it was in Drupal 7. I recommend using composer to install contributor modules or themes.