First make sure you are logged in to your Desmos account.
All of the graphs saved under a particular Desmos account, are accessible by clicking on the three horizontal lines in the upper left hand corner to open up the Saved Graphs menu.
Your saved graphs will be visible in chronological order, starting with the most recently opened graph. To find a particular graph, you can scroll through the list or search by graph name. To search click on the magnifying glass icon and type in the title of the graph you're looking for.