How to restore to a back up?

[tomtendo]

Backed up before Yosemite, how do you go back? I'm not running Yosemite just yet, but would like to know this before, incase I encounter any problems.

 

[Apple_Robert]

When you boot into recovery, you will be presented with the option to install a new OS or install from a TM back up.

 

[tomtendo]

When you boot into recovery, you will be presented with the option to install a new OS or install from a TM back up.

What boot key do u push?

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When you boot into recovery, you will be presented with the option to install a new OS or install from a TM back up.

nvm got it. cmd+r before apple logo