How do you replace tappets on a Peugeot 307 1.6hdi?

To replace the tappets on a Peugeot 307 1.6 HDi, first, ensure you have the necessary tools and parts, including new tappets and a gasket set. Begin by removing the engine cover and timing belt, then take off the cylinder head to access the tappets. Replace the old tappets with the new ones, ensuring they are properly seated, then reassemble the engine in the reverse order, taking care to torque all bolts to the manufacturer's specifications. Finally, recheck the timing and ensure everything is securely fastened before starting the engine.