To access the sump plug, you will have to remove the undertray
Firstly undo the 10mm retaining bolts. Caution - the undertray is heavy and must be fully supported during removal
Don't forget to place a suitably sized receiving tray beneath
Using an 8mm Allen key 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 - replace undertray