Why would you want to use a permalink instead of just linking to the blog?
Blogs organize content by displaying posts in reverse chronological order. If you send someone to a blog’s home page and the blog gets updated with new content, the post you referred to may not be so easy to find.
Each individual blog post has a permalink (permanent link), and if you use that, your readers will always end up in the right place.
Here is a brief video that demonstrates how to find the permalink for a blog post.