How to add the blogs and link them to the frontend?

You, as admin, can manage blogs from the admin panel itself. 

Admin panel>blog section> click the upper three dots to add a new blog category. 

You can define the root category or add the new blogs to existing categories. Once you post a blog you can link the blog in the blog post list and link it to any category defined earlier.

For more info on managing blogs, follow this article: