You can run searches that have previously been saved by simply opening up a list of saved searches and clicking the one that you want to run. Alternately, if you know the name of the saved search, in the search query, you can type search. followed by the search name.
Note: As you begin typing "search", a dropdown list with the names of all saved searches opens. Typing more characters of the saved search name narrows down the list. You can either complete typing the name, or at any point, select the desired saved search name.