So I'm gonna break it down for you. I don't do it the official "blogger" way, but I do it the NO-KNOWLEDGE-OF-HTML-WAY - which I'm hoping is a way that will work for you...
First things first, make your buttons. I literally just make little boxes that have words on them. I try to make sure the boxes are all the same size so that they lay in a straight line perfectly on the top. I also try to make sure that they're the same color as the background of my blog. This makes it seem like there's just words to click on and that there isn't an actual "box". So go ahead and make your tabs. You could use a program like picnik.com that's free and totally easy to use. Example tabs - HOME, ABOUT ME, CONTACT, ETSY SHOP...
Once you've made them, upload them to a free photo hosting site. I use flickr, but some people use photobucket. Just pick one and upload them. When you have them uploaded, there should be a way to snag the html for that image. I use flickr, so I can only show you where you can find the html on that site.
That's the html that you're going to need to post your TABS at the top of your blog.
Here's an example of what your html will look like.
When you have all of the html pasted and listed, save the gadget and then drag it all the way to the top right under your banner. It's now on the top.
But now you need to put links attached to each tab. How do you do this?
Easy! Make blog posts dedicated to each tab. An about me post, a contact me post, an etsy shop post, etc. The trick is to DATE the post a few years back so it doesn't show up on anyone's feed (like on google reader). All my posts are dated for 2001. This will also put these posts to the very very back of your list of posts.
Once you make these posts, make sure to LABEL each post according to what you want your tab to be. So, my about me post is labeled - ABOUT ME. My PHOTO tab is labeled photo. Every time I blog about photography, I label it Photo and so when you click on my Photo tab, it'll show you all of my posts labelled in that way.
Publish it! Publishing it will give it a link. Click on your label at the bottom of the published post to get a link.
See the label PHOTOGRAPHY at the bottom? That's where you click to get your entire feed of everything you've labeled with that specific label.
Once you've done all of this - and trust me, it'll take you awhile - save and it should all be done! I like to center all of my buttons with
I hope this isn't too confusing! Let me know if it helps!