Hi Yicheng and others who have not been to Canada Heights before. Directions are a bit complicated, but here goes...
Leave the M25 at J3, then take the A20, straight on at the 1st roundabout, then 1st left into Button Street. Canada Heights is the first turning on the right AFTER the Farningham Wood Nature Reserve.
Here's the map and satellite image to help you. The satellite image shows the track. The car park is anywhere you can find a space after you pay to enter the facility.
