Step 1: Highlight the type of entity you created

For example in the picture below we are highlighting Organization.

Step 2: Find the Entity in the list

Look in the second window on the left for the instances of that entity you have created. The name listed here is the name you gave it when you first created it. You can search by using the search box below it.  Highlight the entity you want to edit.

Step 3: Click on the Edit box on the right panel.