I want to change my website so that I can use WP plugins and make the site easier to manage, can anyone point me to a document or site that tells me how to do this?
Look on google for the WordPress codex or if you don't have time hire someone Pm me if you need help or my services
I have done that to a few sites, and it's easy enough if you are familiar with WordPress. To use WP plugins, back up everything from your html site and then install WordPress instead. I know that almost sounds too simple, but it's not difficult. If you are concerned about it and want to try before you commit, just install WordPress to a new page on your existing site for practice. You don't even have to link to it from your current site, so only you will know the URL. If you want it to look similar to the old site, just select a theme that has a similar layout. (I use Artisteer to create themes, and you can easily tweak the design to get very close to the old site.) Once you have your WordPress installed and theme applied, then it's just a matter of adding your content back into the site. Not knowing what was on the site makes a recommendation difficult, but this is where you can use plugins for more complex content pages.