The sump plug located on the base of the engine, it is accessed underneath the car. You will need to remove the undertray
Don't forget to place a suitably sized receiving tray in place!
With a oil catchment tray in position, Using a 21mm spanner or socket, carefully remove the sump plug and fully drain the oil.
When the sump has emptied, wipe clean the sump plug area with a paper towel and refit the sump plug and washer
Replace (new) sump plug and washer. Do not over tighten. Reinstate the undertray
Firstly undo the 10mm retaining bolts. Caution - the undertray is heavy and must be fully supported during removal