Hi, I did just this a few weeks ago on my 98 LS400. Make sure you have a large bucket/container to capture all of the oil which will be released. First you need to unbolt around ten nuts which hold the large plastic moulding/cover under the engine. The oil sump nut is straightforward as it only needs to be unscrewed with a suitable sized spanner. Be careful not to round the edges on the nut otherwise you'll have to try and get a local garage to help you loosen it. Next, the oil filter can be removed by hand. If this does not work then try pushing a long screwdriver into the centre of the filter via its sidewalls. This will allow you leverage to turn the filter, hence unscrewing it. Last thing, make sure you dispose of the oil and the old filter as per your local environmental recycling procedures. Good luck, you'll feel good after having done this job. For my first attempt it took me around two hours, but next time it will definitely not take as long.