Louise, I think I mentioned Blogger which is the easiest to start on. Click on the link, sign up -- everything is self-explanatory. Probably should think about what you want your blog's name to be. Blogger gives you the web address for your blog-- your URL. The first blog I started about 10 years ago, I wanted to call it Journey to Find. Blogger gave me the address http://journey2f.blogspot.com.
Since then I've added my Rhine Girl family history blog. http://rhinegirl.blogspot.com.
Once you're signed up, pick a template. Blogger takes you to the page to do this. You need not stress over this because you can change it to your heart's desire. Mine has probably been changed at least a dozen times. The easiest way to start is just to pick a one-column simple page. You'll grow your blog with time and add side bars and much more.
Then you more or less fill in your "layout" page. You don't need to add any pictures or anything at this point if you don't want to. You can simply click on "new post" and write your first blog post. You can always add things and dress up your layout as you go. Look at other Blogger member blogs and get ideas from them.
Most of the time I write my posts in Word and copy and paste to my blog, but sometimes I write directly on the new post page in Blogger. You don't have to "Publish" your blog if you don't want to. It saves by itself, so you can always go back to your post and edit, add to, or delete. When you get to the point where you want to publish to the internet, you click on the button that says "publish." You can still go back and update any time you want. Then you just keep adding posts. The rest will be "history!" b.