In order to access your Windows 10 Advanced Start up options please hold down the shift key while performing a normal restart by right clicking on the Start button on the lower left of your screen:



Your system will now restart into the Advanced Start up options, this can be useful if you are attempting to boot from a USB, perform a System Restore or enter Windows in Safe mode:



Here are a few more ways to enter your Start up settings:


https://support.microsoft.com/en-us/help/4026206/windows-10-find-safe-mode-and-other-startup-settings