MLA annotated bibliography help?

I understand that there is two parts on every source, one is citation part and the second is the annotation part like the summary? If I have room to type more after a citation do I start my annotation part on the same line or do I press enter? Do you put headers on an annotated bibliography and if so what info. full name? date? cl? Do you put a title on the top of the page like “annotated bibliography”? And everything needs to be double spaced right? Also what order in alphabetical by author what if there is no author? I’ve been to Purdue Owl and other universities resources but their not to helpful.