Moving from a non wordpress site to a wordpress and 301s

Hi, We had a site built for us and they used a platform called Xara. This proved so difficult for us to update we want to change it to WordPress which is what the subdomain blog is run on and is wonderfully easy for us to add to.

The old pages are all copied and in draft form on the WordPress subdomain blog and we think we know how to handle the change over with a lot of help from Hostgator.

What we don’t know is how to handle the 301s. All the old pages are .htm at the end which don’t seem to be on WordPress pages. Should we just add this to the URL and call all the pages the same? Or is there a better way to handle this? The old pages are ranking well and so we don’t want to loose that.

Please note we are very good chiropractors but completely rubbish at html so answers may need to be in words of one syllable!

Many thanks.
Sophie