Step 1: To set up Automatic Replies, click the Settings gear > Automatic Replies. Then a window will appear on the screen with a list of options. Click the option Send Automatic Replies. And if you please, choose the option Send replies only during this time period, which will automatically send out the replies during a set time and date that you choose.
Step 2: Then, located at the bottom of the screen, in the text box compose a message that you want to be sent out while you're away. Below the text box are two options; Send replies only to my senders in my Contact List, so the automatic message doesn't go to spammers and you aren't giving away any personal information, or Send automatic replies to all external senders, so you don't miss a new client. Then click OK, located at the top of the window to save all changes.