The sump plug is located on the base of the engine
You will need to remove the undertray
Undo the fixings - use a 10mm socket
Carefully remove undertray. It is heavy
Don't forget to place a suitably sized receiving tray beneath
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 fit a new sump plug and washer
Do not over tighten. Reinstate the undertray