One post on frontpage

Anything is possible (well, almost!), you just have to first work out exactly how you want it!

Do you mean that you want the whole of one post on your front page and then the others listed in the sidebar?

If so then you would need to set your front page to a static page (‘Setting –> Reading’ in you backend) and then look for a plugin that will do what you want to achieve in the sidebar.

Try searching for ‘display post excerpt’ under ‘Plugins –> Add New’ and see if they would be any good for you.

I would like to do it without plugins if possible.

If I use the loop on the frontpage and change the “how many posts to display on page” to 1, that should work, but how i show the remaining posts at the side div with titles/excerpts?

You can run query_post($args); again, with $args being your array of arguments, such as category, number of posts, etc. –

query_post($args);
if (have_posts()){
    while (have_posts()){
        the_excerpt();
    }
}
wp_reset_query();