Default Page inconsistant

Hi,
So I created my own blog which seems to have a default page. So I create a couple more for my nav bar menu. But when I create a new post, it seems to default to the default page. What I want to be able to do is to edit the page of my post after I have written this, can I do this? Under settings there is an option to make a page static but the default page is not in this list, am I supposed to delete this page and replace it with a new created one of my own?

Thanks for your help.