Sticky post is a post which will be always on top of home page and all the following posts will be below and standardly go from home page to the next.
In order to make a sticky article on home page, you should in Administrator console click on Posts and select post which you want to make sticky. Then, select block Publish. Drop down menu will be opened and near item Visibility you should click Edit.
Menu items will be opened where you need to tick checkbox in Stick this post to the front page and click OK button.
You need to click Publish button in order to add post to front page.
You can also stick a post by using Quick edit.
To do this, go to menu Posts → All posts, hover the cursor over title of necessary article and you will see the link Quick Edit, click on it and block with settings of this post will be opened. Click on tick Make this post sticky on the right of page. Click on Update button.