Having installed Website Insight and Imagemapper I am totally confused as to my next steps.

Is there anything out there that details step by step what I need to do next and why etc etc.

Regards Andy T

With insight enter the url to your site. http;//mydowmain.com. Insight will analyze and let you know of any recommended changes.
With site mapper enter your url and let it build a map of your site links. Now upload this to your host. Then go to Google webmaster tools and point it to your sitemap.xml.
I see you actually typed image mapper. With that grab an image that you want to add links to. Now use the built in tools to link various sections of your image. Add the generated html to a page and upload the image to your site.

I meant to type site mapper Eric. ..

If I was doing a domain that has a sub section such as www.cyberbuyer.co.uk/osclass would I use the full path or just the domain in insight?

If you want to analyze a sub domain then I would type the path to it.