I'm having trouble preserving paragraph formatting when pasting content from Notepad.

You can usually preserve paragraphs when pasting from Notepad (or other plain text editors) by making sure there are two newlines between each paragraph, e.g.:

Lorem ipsum dolor sit amet, consectetur adipiscing elit.

Duis diam dui; ullamcorper id, sagittis at, dictum vel, augue.

Pellentesque habitant morbi tristique senectus et netus et malesuada.
If a normal paste doesn't work, you can also use the "Paste as Plain Text" function and use the "Keep linebreaks" option to preserve paragraphs. The button is the fourth from the left.