If you want to relay the postings of your blog onto Facebook, you need the services of a site like Twitterfeed.com. There are several other similar providers. You open an account with the site, and once all done you click on "Create new feed".
You name the feed (e.g. give the name of your blog) and copy the URL of the blog into the second box. Before you proceed further, I do suggest you tweak the Advanced Settings, particularly the Post Content section.
In the 2nd step, you configure the service you want to copy your feed onto, Facebook is included. You will be prompted to Authenticate a FB account (if you are a first-time user of Twitterfeed), or select an existing account.
Finally, you click Create Service, and in the next screen All Done, unless you want to add another service (e.g. Twitter).
Twitterfeed checks your feed (blog) for updates every half hour, so updates are posted pretty quickly.