First you will need to create a new page. Navigate to Pages > Add New. Give your page a title of “Blog” (this can be anything you want). Leave the page template as the default template. Next, you can assign your page to be a full width, left sidebar, or right sidebar layout. See the page section for details on setting up pages. Lastly, click “Publish”.
After you have created your blog page, navigate to Settings > Reading. Select the drop down for “Posts page”. Find your blog page in the drop down list and select it. Lastly, click save changes. Open the blog page you previously created and refresh. You should see the “hello world” post that WordPress puts in by default.