Canon RebelT3i EOS 600D Instruction Manual page 25

Getting Started
This chapter explains preparatory steps before you start
shooting and basic camera operations.
Attaching the Strap
Pass the end of the strap through
the camera's strap mount eyelet
from the bottom. Then pass it
through the strap's buckle as shown
in the illustration. Pull the strap to
take up any slack and make sure
the strap will not loosen from the
buckle.
®_ The eyepiece cover is also
attached to the strap (p.262).
Eyepiece cover