When you want to create a text block that you do not want to re-use elsewhere, you can choose the "Text" block. It just exists on the one page where you create it. It does not appear in the list of "Notes" under "Content".

If you want to create a text block that you can re-use in other pages, e.g. information about your hobbies and school activities, instructions for an activity etc., you can use the "Note" block.

During the upgrade, all notes that have not been used in other pages, don't have a license attached, don't have feedback and don't have any attachments, will be converted to simple text.