First of all, you need to create required pages and select it for front page display:

  1. Go to Pages > Add New
  2. Input some page name, for example, Homepage (we will fill it some steps later)
  3. Publish homepage page
  4. Go to Pages > Add New
  5. Input some page name for blog, for example, Blog and Publish it
  6. Go to Settings > Reading
  7. Choose Front page displays option "A static page", select Home page that you just created for Front page option and Blog page for Posts page option:

          8. Click Save settings