Need step by step guide on how to service a toyota yaris

Firstly look at the part numbers of the items you want to replace, oil filter, spark plugs, if you want to put new ones in, air filter and if the car has quite a high mileage, the fuel filter. The fuel filter is under the car and looks like an alumimium cylinder. If you go to a quality spares shop they can sell you reputable parts, often for a lot less than Toyota original parts. Ask them to set the gaps on the plugs and buy a gallon of the type of oil that is specified in your handbook for your type of climate. You will also need a sump plug washer.

The first thing to do would be to remove the air filter from the cleaner. This is usually held together with clips and/or screws. Clean out the inside of the housing and place the new filter in the same position as the old one. Clip and screw everything back together and that job is done.

Blow around the spark plug holes, number each spark plug lead from 1 (front of engine) to 4 (back of engine). Remove the plug leads and the unscrew the plugs. Replace with the new plugs being careful not to overtighten them and replace the plug leads onto the correct plugs.
Check your engine coolant level and top up if necessary.
Start the car and get it to normal temperature. Switch off engine. Chock the wheels, put the car in park or gear and handbrake on. Jack up the drivers side giving you enough space to slide a bucket under the engine. DO NOT GET UNDER THE CAR. Wipe around the sump plug and SLOWLY undo it. The plug is at the bottom of the sump at the lowest part of the engine. THE OIL ON THE OTHER SIDE OF THE PLUG IS HOT SO TAKE CARE. Let the oil drain. Whilst this is happening, wipe around the filter base and unscrew the filter. This will also be hot and oil will spill so make sure that the bucket can also catch the spillage. Wipe away any excess oil and make sure that the rubber seal has not been left on the engine. It is important to remove it. Place a smear of new engine oil on the new filter rubber seal and screw the filter in place. A good hand tightening is enough. By now all the oil will be out of the engine and you can replace the sump plug washer and screw the sump plug back into the sump making sure it is tight. Wipe away any loose oil. Remove the oil filler cap and pour about half the oil into the engine. let it settle for a minute and remove the dip stick, clean it off, and dip it again. You should see the oil level near the bottom of the dip stick. Add another pint and check again. Keep going until you reach the full mark. Replace the oil cap and dip stick and start the engine. Run it for a few minutes and check the filter and sump plug to make sure they are not leaking. Switch off, let the oil settle and check the level again. It will go down because the filter is now full. Top up and you are done. Look around the engine bay to make sure nothing is amiss. If the car has done about 20 000 remove the wheels and check the brakes have enough lining. Check the tyres for tread, cuts and so on. Make sure all your lights are working. Now you are pretty much good to go.