To use the advanced HTML editor
By default, you can update website content using a simple content editor. Move the mouse over the text you want to edit. If it is editable, you will see the "Editable area" information. Just click on it and start editing. When you are done, click the "Save" button.
You can edit the HTML code (recommended for advanced users only) if you need more control over a content block: Move the mouse over the content block you want to edit and the toolbar will appear in the upper left corner. There is a SETTINGS button, click there to edit it Open the content block settings.
A new window appears and on the left side there is a button "HTML". Click there to open the HTML editor.