I have always used the code editor but am trying to build a new site using the visual editor since I don't know how to do many of the things with placement - I have done a page that looks fine in the editor preview - but when it is opened in Firefox everything is in the wrong place - Internet Explorer is even different. When it is simply previewed in the preview pane there are things like little squares before some of the text. I don't understand why I can put things where I want in the editor and it looks fine but is all screwed up when viewed as a webpage - what is the point of having a visual editor if it doesn't know how to make the page look like the editor? This is turning out to be very complicated and time consuming. Also it is difficult to move things around anyway - it will let me one time and other times it won't. If you want to move something down below things that are already on the page it won't let you - it's just illogical!

The visual editor uses CSS and absolute positioning when you move things around as you are trying to do. For this reason, you need to understand CSS in order to know how to avoid the problems you are having with page elements changing position depending on how you view them, whether in the editor or in a browser.

I have been making my first website using css, for a friend, sitting for now on my own hosting.
http://artofnow.org/elisabeth/v2/index.html

I use the html editor (build 302) - and use the visual editor tab to edit the layout of the main block content.

I am used to the visual tab changing the content type charset and always have to change it after a visual edit.

But now it is moving the content in my css block "main"

So if you look at the website ... the subpages I have not edited with the visual editor tab sit nicely
and the ones that have been visually edited (home, contacto,...) are displaced.

I have played about with css block sizes to no avail.
I have gone through the html code to see what is different and can't find anything

So now a bit stuck. Any help very welcome.

Sounds like you are swapping back and forth between the 2 styles of editors within the program Norman. You can't really do that functionally as they are 2 separate systems. You need to make a choice between either the Code or the Visual style and stick with that tab only on each page you're editing and not go back and forth between them. Anytime you change between them you will end up with a ton of code changes that you will have to constantly fix. Very nonproductive other than for the learning of how things are setup. Placements are one of the most prominent things to see that they will change code on between the 2 different systems.