Apple Posts How-To For OS X Recovery

OS X 10.7 Lion and later include OS X Recovery. This feature includes all of the tools you need to reinstall OS X, repair your disk, and even restore from a Time Machine backup.

OS X Recovery includes a built in set of utilities as part of the Recovery System. You can use OS X Recovery to do the following:

– Restore your Mac from a Time Machine backup.
– Verify and repair connected drives using Disk Utility.
– Check your Internet connection or get help online using Safari.
Install or reinstall OS X.
– To start your computer from Recovery, restart your Mac and hold down the Command and R keys at startup.

Apple Support has posted a how-to tutorial on using OS X Recovery here:
https://support.apple.com/kb/HT4718