How to edit a text side block
Step 1.
Make sure you have the rights to edit the page and the block it self.
Step 2.
Navigate to the page and hover you mouse on the top-right corner of the block. You will see a clickable gear icon. When you click it you will see the option Configure on a new button and by clicking this option you will be re-directed to the block’s configuration page.
Additionally you can navigate to the page from Structure -> Blocks -> Find block’s name -> select configure.
Step 3.
On this page you will be able to edit the block's text and Title. Please note that there are two titles the block title that will be presented in the site and the block description that will be presented on the blocks administrative page.
Step 4.
Make sure you click on the save button before you close the tab or your edits will not be saved.