This vid is somewhat helpful but doesn't show how to tackle the more complicated rear head and it's better to advance the motor via the crankshaft and by removing the cam tensioners the cam gears and cams can stay together. It's best to first paint a horizontal line across everything (timing chain and gears) once TDC is reached for reference. The balancer nut on the rear head is torqued on and hard to remove. There's good info and pics on the Haynes Gen 1 manual that carries over for Gen 2. Make sure the cam chain doesn't slip from below and keep rags stuffed in the exposed engine in case something falls in
One more thing about removing the tensioners- the radiator manifold and 2 small hoses has to first be removed to access the tensioners- the 2 small hoses are a very tight fit against the frame. After adjusting one head make sure to first re-tighten the tensioers before advancing the motor to TDC otherwise the timing chain can slip and use new washers on the tensioners and torque to specs