Need help in simple terms on editing exsiting webpages

Hi I just want to edit my webpages online with ckeditor I know how to get the editor up, but in simple terms how do I GET IT TO EDIT and Save content(write and save ) the content to an exsiting webpage being .php or .html ??? what do i have to do to my exsiting pages to make ckeditor and save them ? iv look at the intergration still cannot figue it out been at it all day please help