In settings ==> Reading - I can only add "Your latest posts" or Static page. maybe there is some plugin, so I can add 1 post on my front page?
When writing post, on the right in the Publish box, look for visibility it may be set to Public, click the Edit link just next to it, Enable the checkbox that says Stick this post to the front page. Click Ok. Done
Yes, it is easy to do it. - Log into wp admin mode - Click on post (left side) - Find the post you want to stick - Click on quick-edit - check the "Make this post sticky" Santacruz