Please note this option is available on iOS only
You can first select the post you wish to make as a Sticky post from My Site > Blog Posts.
After you open up the post editor, you can then tap on the three dots in the top right and select Post Settings to view the settings for that post.
Next, scroll down and enable the option to ‘Stick post to the front page’
And head back to the post editor and Click ‘Update‘ on the top right corner to save the changes