You will need to be able to work under the car. I think the drain plug needed a square or hex drain plug key/allen key. You need something to catch a few litres of oil. To refill the gearbox you will need a length of suitable tubing as, unless you have a large syringe or similar, you need to fill it from the top of the car. Make sure that you can undo the filler/level plug before taking out the drain plug. On my car, there was no drain plug washer which didn't seem right, so I used a compressible aluminium washer (spare sump plug washer, if I recall).
It's easy.