List categories with post titles only, in posts page

hi
in Admin> Settings> Reading> i have set my posts page to an empty published page . When I click on it, it shows me all my posts in chronological order, displayed fully from start to finish. this makes a very long page! This must be either my archive.php or archives.php template being used.

what i need is a list of my categories displayed on this page instead. under each category heading would be a link to each post, displaying the title of the post only. a maximum number of 10 posts per category would be great also. where do i start?

HH