"can't get out of Windows 10"

Restart while holding the option key (it has "alt" written in much smaller font, as a gesture to PC geeks like Ben).

In OS X, open Boot Camp Assistant, and download the "Windows support software". Then boot to Windows and install it. You will need that for Windows to have Wi-Fi, trackpad gestures, sound, a Boot Camp control panel to choose the startup disk, etc.

<0-0>

Restart and hold the alt key and it will give you option