Can't get map to download!

Hello. Just started looking at this site & had a lot of problems.
So I have chosen a simple start example.
I input a single UK post code & clicked on export.
I chose to open with Open Office Writer, because that is the package I use.
The output was just a long list of typing.
So what am I doing wrong?

That outputs an XML-file. A .osm-file contains all the information in the exported area as XML. That is what you are seeing.

If you want an image format, you have to click the square with outgoing arrow on the right