How it displays excerpts, not full-text blog on home page?

can you please explain me. how do i display excerpts text.

• Go to Posts → Add New in your dashboard to create a new blog entry. Note: this does not work with Pages.
• Begin writing your post. When you decide that you want to cut it off, insert the More tag to split the post (mark where the excerpt officially ends). You will see the More Tag as such in the visual editor: http://prntscr.com/7fn6s0
• Finish writing your post.
• Publish the post and view the front page of your blog. You should see your post effectively split using the More Tag. Note: The more tag is not displayed in post previews, since previews display posts in entirety, but the more tag will appear once the post has been published.

Hope this helps !