The sump plug is located on the base of the engine, and it is accessed from underneath the car
Don't forget to place a suitably sized receiving tray in place!
With an oil catchment tray in position, use an 8mm Allen key socket to 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 re-fit the sump plug and washer. Do not over-tighten
Replace (new) sump plug and washer. Do not over tighten