Electric 4 inch Chainsaw

This electric chainsaw feels comfortable in my hands. The weight, shape and operation are similar to a battery operated drill. I was able to put it together quickly with no issues. The extra chain is important as I am left with a very important question, Where do I oil this chainsaw? After short use, the chain is loser than I would like and I’m baffled on how to oil the device in order to encourage longevity of the chains. I was able to cut through a 4in dead branch without issues or hesitation. I have also used it on live trees with no problems.