You first have to upload your audio file to a file sharing service, then link to its url on your blog post. Here are the steps.
1. Save your file in either .aif or .wav format
2. Join FileDen by going to their web site FileDen.com and registering. It's free but — warning!! — you will have to wade through a lot of ads. Just keep clicking on Skip This Ad.
3. At the top of the FileDen web page, click on Upload.
4. At the bottom of the Upload page, click on Browse Files and select your file.
5. No it hasn't started uploading yet. At the bottom of the same page, click on Start Upload. You should see a progress bar.
6. When it is finished uploading, you will see its URL. Copy this information.
7. Open the New Post window for your blog.
8. Go into Edit HTML view and paste in the following code:
<embed src="URL_OF_YOUR_AUDIO_FILE" autostart="false" loop="false" controls="console" height="62" width="144"></embed>
9. Highlight "URL_OF_YOUR_AUDIO_FILE" and paste in the actual URL from step 6.
10. Publish the post, view the blog. You can of course add other text, images, etc. to this same post.
Here's an example: