The Manage Form Display page for a Content Type determines how the content will be added to the data base, by creating a form based upon the fields entered in the Manage Fields page.

You will notice the + symbols in front of each field. That field can be moved on the form by click on the + symbol and dragging the field to the desired location.

Some of the fields are automatically added by Drupal, If you do not need them in the content, you can move them to the Disabled location at the bottom.

The gear for each field will open the parameters for that field in the form, like the number of lines in a text box.