Don't 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 and fully drain the oil.
When the sump has emptied, wipe clean the sump plug area with a paper towel
Replace (new) sump plug and washer. Do not over tighten
Find a Haynes product for your Seat:
Search by registration mark
Search by make & model