Instructions
Go to the Sawmill. It is located northeast of Varrock. You cannot bring any familiars or pouches with you when you enter, and you must have at least Level 80 in the woodcutting skill. You must bring a saw, but the rest of your inventory should be empty for holding supplies.
Talk to the Overseer to learn about working at the Sawmill.
Click on the job board near the Overseer to select an order of planks.
Gather logs from the stacks by the job board until you have a full inventory.
Use your logs on the conveyor belt hopper to load them in. The auto woodcutter will form the logs into planks and drop them into a collection box.
Collect the planks and then use them on one of the workbenches. Select the type of plank you want to cut.
Load the finished planks into the cart by the Overseer. Continue this process until the cart contains all of the planks for your selected job.
Talk to the Overseer again to complete your job and the cart will be emptied.