Using Text Blocks Tutorial | Squarespace 7.1 (Classic Editor)

How can the width of the text block be changed? It seems only to go to a certain width and then it's not modifiable. Spacers can help move it around and make it more narrow, but what's the solve with making it more wide?

And how to change space between lines of text? A bloody mystery! Basic thing that should be easy to find, but it's a bloody mystery.
Also, where to change the size of the bloody text? Another mystery! Damn, improve that text editor! it is terrible! hating every minute of it.

Should your headlines and paragraphs be in separate text boxes or a single text box?

I cant seem to highlight the text even! It just shows me the hand fist icon