You will need to remove the cars undertray
Undo the fixings - use a screwdriver
Now carefully remove the undertray
Don't forget to place a suitably sized receiving tray beneath
Using a 14mm 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 a new sump plug and washer