If you suspend your computer and then press a key or click the mouse, it should wake up and display a screen asking for your password. If this does not happen, try pressing the power button (do not hold it in, just press it once).

How do I get out of sleep mode in Ubuntu?

Open the Activities overview and start typing Power. Click Power to open the panel. In the Suspend & Power Button section, click Automatic suspend.

How do I wake my computer from suspension?

To wake up a computer or the monitor from sleep or hibernate, move the mouse or press any key on the keyboard. If this does not work, press the power button to wake up the computer.