When you create a post, it gets stored for just you. To edit that post either view your journal, and click edit, or go to "List Entries" in the journal navigation and all your posts will be listed there. You can edit a post as many times as you want, and even delete your own posts. One thing to note is that the date that gets displayed with the post is the date & time that you first entered the post, not the last time you edited it. (some templates will show the edited date.)

Each post will have it's own unique page. The benefit of this is that you can allow users to comment on what you write, and it will be displayed on the "single" post page. Each template has it's own way of displaying comments, and this template's comment style is previewed below.