The search function is located in the middle at the top of the screen where the magnifying glass is, it allows you to search all of your content to find what you are looking for fast.
This is a full-text search so it will search your content for words or terms included within.
Enter a familiar word or term that you would like to look for and you will see the list of all content including these words pop up, you can also do an advanced search:
Choose a group to search
Choose a date from and date to
Enter any tags