I have got as far as generating the sitemap but then the next step is as below and I just don't know what to do (never having seen any of this stuff before).
Now you need to upload your sitemap to your server.
If your server supports PHP or ASP, we can help you further.
We have scripts that will ease the task of providing new sitemaps to Google. Alternatively, you can upload the file manually yourself.
YOur help appreciated