I can't get the editor "Paste as plain text" button to work Not sure why - we're investigating. In the meantime, a workround is to use the simple "Paste" button (or CTRL-V), and then apply the "Remove Format" button to the text you've just inserted. This may leave some undesired formatting, such as list or indents, which you will have to remove.

A paragraph is not indented correctly, and has a larger font than normal

You need to set the Format of the paragraph to Normal

I am trying to create a link to another page in the Sutton Poyntz website, but can't find it in the list of pages

Probably, this means that the page has not yet been added to the site's Main Menu. This is a job that can only be done by a Site Administrator

I expected a menu to appear at the top of a page, but it is missing.

This is also a job for a Site Administrator, who needs to allocate the required Top Menu to the page's entry in the Main Menu
A page appears without a Watermark image behind the text, or with the wrong Watermark image Similarly, only a Site Administrator can perform the task of allocating a Watermark image (by means of a variant of the site's page template) to a page
In trying to create a link to another website, it displays a "File Browser" window. Why? A 'feature' in the editor we use, which can actually be useful. But if you want to insert a website adress, dismiss the file browser by clicking the Cancel button and clicking OK in the next window; you will then be taken to the correct window where you can enter the destination address