You can use Boot Camp to install Windows 10 on supported Mac models that have OS X Yosemite installed, Apple advised in a new support document:
Mac computers that support Windows 10
The following Mac models support 64-bit versions of Windows 10 when installed using Boot Camp. Use About This Mac to see which Mac you have, then check this list to see if it supports Windows 10.
• MacBook Pro (Retina, 15-inch, Mid 2015)
• MacBook Pro (Retina, 13-inch, Early 2015)
• MacBook Pro (Retina, 15-inch, Mid 2014)
• MacBook Pro (Retina, 13-inch, Mid 2014)
• MacBook Pro (Retina, 15-inch, Late 2013)
• MacBook Pro (Retina, 13-inch, Late 2013)
• MacBook Pro (Retina, 15-inch, Early 2013)
• MacBook Pro (Retina, 13-inch, Early 2013)
• MacBook Pro (Retina, 13-inch, Late 2012)
• MacBook Pro (Retina, Mid 2012)
• MacBook Pro (13-inch, Mid 2012)
• MacBook Pro (15-inch, Mid 2012)
• MacBook Air (13-inch, Early 2015)
• MacBook Air (11-inch, Early 2015)
• MacBook Air (13-inch, Early 2014)
• MacBook Air (11-inch, Early 2014)
• MacBook Air (13-inch, Mid 2013)
• MacBook Air (11-inch, Mid 2013)
• MacBook Air (13-inch, Mid 2012)
• MacBook Air (11-inch, Mid 2012)
• MacBook (Retina, 12-inch, Early 2015)
• iMac (Retina 5k, 27-inch, Mid 2015)
• iMac (Retina 5K, 27-inch, Late 2014)
• iMac (21.5-inch, Mid 2014)
• iMac (27-inch, Late 2013)
• iMac (21.5-inch, Late 2013)
• iMac (27-inch, Late 2012)
• iMac (21.5-inch, Late 2012)
• Mac mini (Late 2014)
• Mac mini Server (Late 2012)
• Mac mini (Late 2012)
• Mac Pro (Late 2013)
Read more in Apple’s support document here.
MacDailyNews Take: Apple’s Boot Camp. It’s like using a Lamborghini to haul manure.