dates on wordpress

You'd run a query to do this. For instance, it may look something like

$query = new WP_Query( array ( 'orderby' => 'date, 'order' => 'DESC' ) );

You could also order by 'ASC'. I believe 'DESC' will be newest date to oldest, and 'ASC' oldest first to newest, but you'll have to double check that when you build your loop.

More options can be found http://codex.wordpress.org/Class_Reference/WP_Query about half way to two thirds of the way down the page, under the Order & Orderby Parameters title.

How do I run this query? Do I have to do that on ma admin page?

This isn't jquery, this is PHP. You add this code to your page template, and it'll load when the page template is called by viewing it in the browser.

Are you wanting to order your posts by date in your admin page, or on the actual site?

Want to order it on the admin page but would like it to reflect on the actual website

Two separate things. For the actual site you'll need to run a query like I put above. That will return your post ordered by date. For the admin page, you can click on the date column at the top, and that will change the order from DESC to ASC and back again, but when you leave the post listing page and come back, the posts will be back in the default DESC order. There probably is a plugin available that could change that for you, if you wanted the default order to be ASC for the admin page.