Some times spending hours in trying might save you minutes in reading user guides, tutorials, ect.
This is a good tutorial about using the new WordPress block editor (Gutenberg)
https://www.wpbeginner.com/beginners-guide/how-to-use-the-new-wordpress-block-editor/
And something about the using images
https://www.wpbeginner.com/beginners-guide/how-to-fix-common-image-issues-in-wordpress/
WordPress Block Editor (Gutenberg) Tutorial