Full installation instructions can be found on YouTube either by the QR code on the packaging or a YouTube search by product name.Open the product, remove the foam base, expand the basket with the wire frame on the left and right. Open the velcro strips on the base of the basket and slide the base of the wire frame in between the velcro. This procedure is quite difficult purposefully so that a strong frame can be made for the basket. Insert the foam base, install the liner and connect the headrest strap. Take into the car and connect the 2 ISOFIX straps that are on the bottom of the booster to the ISOFIX baby connectors at the base of the seat. Then take the top strap with the 3rd ISOFIX connector and thread under the headrest and in front of any parcel shelf, fix to the top anchor point in the rear of the car. This will raise the height of the booster seat to around 15cm off the seat base. If there is too much slack on the top strap when the adjusters are at their shortest, re route the strap over the top of the headrest. Ensure that the top strap is absolutely as tight as you can possibly get it so that the 3 points of the harness are really tight against the seat. When this is in place then you can fix the headrest strap into place and tighten accordingly so that it supports the basket. The main strength of the booster is of course the straps in the 3 ISOFIX points, the head rest strap is just an additional steadying point. Place your dog into the booster seat wearing a suitable harness and connect the swivel tether to the harness (never to a collar). Adjust the length of the tether if necessary. Your dog and passengers are now safe and secure and the Ultimate Safety Tether incorporated into the booster seat will provide unrivalled protection to your dog under heavy braking or in the worst case, an accident