Restarting Steam is the process of closing and then reopening the Steam client. This can be done for a variety of reasons, such as to fix a problem with the client, to update the client, or to simply refresh the client.
Restarting Steam is a relatively simple process. To do so, simply click on the “Steam” menu in the top left corner of the client and select “Exit”. Once the client has closed, you can then reopen it by clicking on the Steam icon on your desktop or in your Applications folder.