Dipstick is located just to the right of the turbo heatshield, its got a yellow handle. Manuals you just clean/insert dipstick and check against marker levels. Autos are more involved.... oil should be at normal working temperature, leave engine running, apply handbrake, put in D for 15 secs, then put in R for 15 secs, then put into P. Clean dipstick and re-insert, it should be between the MIN and MAX levels, if low top up using DEXRON III, distance between max and min is approx 0.4 litres.