Canon EOS 60D Instruction Manual page 166

Using AF to Focus
You cannot take a picture during autofocusing. Take the picture while the
Live View image is displayed.
166
Focus the subject.
3
Aim the AF point over the subject and
press the shutter button halfway.
The Live View image will turn off, the
reflex mirror will go back down, and
AF will be executed.
When focus is achieved, the beeper
will sound and the Live View image
will reappear.
The AF point used to focus will light in
green.
Take the picture.
4
Check the focus and exposure, then
press the shutter button completely to
take the picture (p.152).