this video is a guide to help make it easier to use your scenario next please be sure to read the complete instruction book which includes important warnings and other information first to adjust the buckle location turn the seat over and slide the metal retainer through the seat put it back into the desired location and pull up to make sure the buckle is secure keep in mind that you must use the first or second buckle slot when installing rear-facing next adjust the shoulder harness to the correct location first loosen the harness by pressing down on the metal adjuster under the pad in the front of the seat and pulling on the harness straps now on the back take off the harness loops from the metal splitter plate then pull the harness straps through the seat back choose the correct harness position based on a child's height when installing rear-facing the harness shoulder height must be at or just below your child's shoulders rethread the harness straps through the seat back keeping the belts flat and untwisted then reattach the harness belt loops to the splitter plate making sure they are all the way on before installing the sanera next in your car read your vehicle's owner's manual this contains important warnings and information to make sure the seat is properly installed place the car seat in the back of your vehicle for smaller children who cannot sit upright unassisted always install the car seat so that the line on the side of the car seat is parallel with the ground children who can sit upright on their own can use the seat more upright in the car now route the vehicle belt through the rear-facing belt path take care not to twist the belt and then buckle the buckle in most cars when the vehicle belt is pulled all the way out it switches to a special mode in that mode the vehicle belt will tighten and will not loosen that tightening mode works very well when installing a car seat when the vehicle belt is in the tightening mode push down on the car seat and pull the belt through the car seat taking up all the slack check the install by pushing and pulling the car seat at the belt path if it does not move more than an inch it's good to go if the seat moves too much try to pull more slack from the vehicle belt or try installing with the latch system or try another seating position in the car now you are nearly done loosen and unbuckle the car seat belts place your child in the seat buckle the chest clip and buckle tighten the harness by pulling the strap in front of the seat adjust the chest clip so that its mid chest level with your child's armpits pinch the harness at your child shoulders to see if it is tight enough if it is tight you will not be able to pinch webbing between your thumb and index finger if you can pinch material pull a bit more on the tightening strap on the front of the car seat