Google provides articles and videos to help you with posting on Blogger. The following was duplicated from Google to assist you.
Posting to your blog
Next, you'll see the Post Editor. Start by giving your post a title (optional), then enter the post itself:
When you're done, click the gray Preview button at the top to make sure it's ready to go. This will open a new tab in your browser where you can see what your post looks like on your blog. You can go back to the previous tab and edit your post further, or, if you're satisfied, just click Publish to publish your post. That's all there is to it!
If a video would help I have embedded the Google Video to help you with your posts.