OK...bear in mind, I have the simplest blog available but if you are just starting, do this and then you might want to get more complicated and search out additional stuff.
First, if you do not have a gmail email acct., make one. Go to www.gmail.com and set something up. YOu never have to look at it again but blogger likes it if you have a gmail acct. It is easy. Just follow directions when you get there.
Then, sign into www.blogger.com and click the orange button that says "Create a blog". Fill out the information they request. Then you will see a page that asks for a title to your blog (and blog address). This is like picking out a "store" name. You might want to come up with a "studios" name if you haven't already. For instance, "red ladybug studio" or "joe blow studios" or simply use your name if you want. whatever it is, you'll type it in and see if it has been taken. This is pretty self explanatory once you are there.
The next step takes you to the backgrounds to pick from. None of these look all that great...pick whatever appeals to you the most. It doesn't matter too much because your blog will be about your art...not the background.
Once you have done that you are ready to post your first public blog. So...as you are going through the above steps, it proceeds to take you to a window for posting. Type in a title to the post, i.e. "my first blog entry", then in the main body start typing what you want to say. Perhaps this is a good time to let folks know what your blog will be about. If you want to add a photo, then click the little blue square icon at the top. If you hover over it with your mouse, it says "add image". Click on it and it takes you to another form page. Click the "browse" button which takes you into your own computer documents. Find your "pictures" file...or wherever you keep your pictures on your computer, find the picture you want and double click it. You will see it pop up in the little window. If you want to add another image, click "add another image" and then "browse" and do it again. YOu can add up to 5 photos for each post. NOW...before hitting the orange "upload now" button at the bottom, choose "center" for the layout and "large" for the pictures. You can change this once you know how it all works but for now, this is best.
Now click that orange button and you will follow the link back to your posting. You will see your pictures pop up in your little window that has text. Once you have written what you want, simply click "publish post" and voila...you are now blogging.
As far as the blog header...I can't help you much there. You don't really have to have one but it adds personality to your site. I have my daughter do it for me. She has done it for other people too. She charges a small fee (not sure how much). You would make up artwork that is sized 9 x 3-1/2. I just pasted a bunch of copies from my journal pages together. Then scan in your artwork at 300 dpi and send it to her and she could put it up. email her if interested at email@example.com. She can also help you with your photo of yourself (called an avatar) or you might be able to do that yourself (I did).
So then, play around with your "profile" and personalize your blog. It is REALLY easy. and it's free. and they are good about taking you step by step even with NO computer knowledge.