Your first cut should be about three feet up the trunk. Make a diagonal cut downwards about 1/3 of the way through the trunk.
Make another cut parallel to the ground just below the first cut that you made. Remove the wedge from the tree trunk.
Make your final cut on the opposite side of the wedge, just above the base of the wedge cut. Once the tree is felled, the remaining stump can be removed by digging a circular trench around the trunk of the tree and severing any roots that you encounter.