Been there? Done that? Planned your categories so that people can follow your blog correctly? Didn't think of that?
Go back now before your stream of consciousness becomes a flood and drowns your prospective readers!
Now, when you are all settled and ready, click on the new post link. You should now see the same sort of thing I can see, which is a nice rectangle to type in and a list of your categories to the right where you can select the main category for this entry and other categories it can also link to.
Just below that is a set of radio buttons where you can decide whether or not to cast your pearls (of wisdom) before the public. You can also decide if you want to risk allowing people to comment. If you do allow comments then keep an eye on them or you can end up with spam,
Just above the writing area are a few controls that let you have bold type, italic type or insert images and hyperlinks. After you have used each tag click on close all tags or you may get some strange results.
Unfortunately for the image and link tags you will need to know the location before hand - there seems to be no browse facility for local files.
Also note for links and images you should type a short description before closing the tag e.g a link to a well known website
Type away, set visibility to public, click save, and there you are exposed for all the world to see.
The more perspicacious of you will have observed two tabs at the top of the input area, labeled Simple and Expert. Try the expert setting if you wish but you will need basic web editing knowledge to make best use of it.