Check chain lubrication by turning on the chainsaw and running it near a dry piece of wood or paper. The chain should throw off a small amount of oil when properly lubricated.
Clean the area on the Stihl chainsaw near the oil filler cap. The cap is on the left side of the chainsaw, just behind the chain and bar,
Remove the cap and check the level of oil inside the reservoir. Add oil until the reservoir is full.
Replace the cap on the Stihl chainsaw, screwing it tightly into place.