When you ar inside the page (layout creation page) you are working on, its only the maine objects who are visible and you have to pick the category that your object is in to pick the one you want og you can pick manage.

The blog are easy to set up in section 4. You have to set the layout and the comments metode that you find by click on them at the top of the page - and then you can make your first article inside the one that named "post".

Then you go to section 2 and add an new Level in the site map creation, give the map the name you prefer (blog or something) and then go to the bottom of the page to the special page maps and pick that who named blog and drag it inside the new level you have created earlier - if I remember right.

Hope I have understand your question right and it was this you was looking for