The Properties panel is where individual settings are found for various features within the program.
The Properties panel adjusts to show the settings of the currently selected feature. For example, a hotspot selected in the Viewer will have its parameters in the Properties panel.
Use the text editor to write in plain text, rich text, and Markdown. Commonmark is the flavor of markdown that is supported in the editor.
The Text/Markdown tab is for writing plain text or Markdown.
If using Markdown, select Markdown.
Use the Visual tab to write rich text. Here, you can choose the text style from the menu. The default is Standard. Next to the list is the option to change the text to bold, italic, and to a web link.