Where do you oil a chainsaw?
Your chainsaw needs several different types of oil.
Firstly it is going to need two stroke oil mixed in with the petrol. The ratio should be marked on the filler cap, but with modern engines it's usually fifty to one. I.E. 100ml of oil for every 5 litres of petrol.
Next it needs chain oil. Chain oil goes into the oil tank usually on the side at the front of the saw. Chain oil is a special formulation that is high cling. It's sticky and somewhat stringy so that it stays on the chain and bar longer. Never run your saw without chain oil. You'll ruin the bar and very probably the chain too.
Thirdly you need to grease the drive sprocket and the nose sprocket every now and then. Some people never grease the nose sprocket in the belief that it just attracts crud and that the chain oil is enough. I'm one of them, but I grease the drive sprocket weekly. To do that you use a small grease gun that should have come with your saw, otherwise they only cost $5 or so.