The sump plug is located on the base of the engine, it is accessed underneath the car. You may need to remove the undertray - Caution! This is heavy, and must be fully supported when removed
Undo the undertray fixings - use a Torx-25 tool to do this
Carefully remove the undertray. Here is the sump plug
Do not forget to have a suitably sized receiving tray in place!
With an oil catchment tray in position, use a 19mm spanner or socket to carefully remove the sump plug. 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. Do not over tighten. Replace the undertray.