Up to this point in the installation process, the installer has made no lasting changes to your computer. When you click Begin Installation, the installer will allocate space on your hard drive and start to transfer Fedora into this space. Depending on the partitioning option that you chose, this process might include erasing data that already exists on your computer.
To revise any of the choices that you made up to this point, return to the relevant section of the Installation Summary Menu. To cancel installation completely, click Quit or switch off your computer. To switch off most computers at this stage, press the power button and hold it down for a few seconds.
After you click Begin Installation, allow the installation process to complete. If the process is interrupted (for example, by you switching off or resetting the computer, or by a power outage) you will probably not be able to use your computer until you restart and complete the Fedora installation process, or install a different operating system.