Tutorial - Posting Trades - Adding Commentary:
When you post a trade, if you want the commentary to be in separate paragraphs for the opening comment and closing comment, you'll have to post a trade as being open, first, which will only have you enter the entry price and entry comment. Then, you will go to your open trades and close the trade out, separately. This will allow you to enter the closing price and any commentary you add will appear in a separate paragraph in the trade details.
If entered and exiting a position and only care to make one block comment on the trade, you can initially enter the trade as a closed position, which means you'll enter both the entry and exit price, and the commentary will be in a single block of text, regardless of whether or not you enter blank lines in the text field.