Most computers do not start automatically on the Tails USB stick, but you can press a Boot Menu key to display a list of possible devices to start from.
If Windows 8 or 10 is <span class="linux upgrade-linux">also</span> installed on the computer, you can refer instead to the [[instructions on starting Tails from Windows 8 or 10|doc/first_steps/start/pc#windows-restart]].Starting Tails from Windows is easier than using the Boot Menu key.