Removing Author, Date, Category… from Post

Hi all (and thanks in advance for your help!)

By default, when publishing a New Post, under the content I can see:

Author
Date
Category
Search bar
Article Information
Recent Posts
Archives
Categories
Meta

My aim is to hide them and just have the content of the post showing.
—
I have tried a few instructions I have found for other themes (mostly overwriting “functions.php” with new instructions), but I ended up having to get it back to the original file.
As I am quite new to wp, I can’t figure out if it’s something to to do with the theme, or with wordpress itself.

Thanks heaps!

Mattia