basically, use whatever grade the handbook says to use. The get some oil of that grade you like...wether it be mobil 1, magnatec, elf, or halfords.
The let the car cool down a little, till you can put you hand on top of the engine and its mildly warm.
-put a big oil tray (or any container that can hold the oil thats gonna come out) under the sump drain plug.
undo it, you will got oil on your hands, so have cloth close.
-go to the top of the engine and take off the oil filler cap (will help the oil drain out faster.
-wait till its all gone.
-discard oil in the correct manner.
-unscrew filter (oil will come out)
-new filter will have the rubber seal dry, put a little clean oil on the rubber seal with you finger. then screw it on....some people say fill it up first, but itll just spill everywhere!
top up the car with the correct amount...or just keep checking the dipstick level. Turn over the engine so you can circulate oil through all the oilways, then check dipstick again....full? no...top up....yes, finished.