Place the adze into a table-mounted vice. The handle should be gripped by the vice with the edge to be sharpened pointing straight up.
Grasp the coarse metal file with both hands, and press the file against the blade. Hold the file at the same angle as the edge of the blade.
Slide the metal file along the length of the blade, pushing up and away from you as you go. You want to press the metal file against the whole length of the blade moving in one direction with each swipe. Start with the metal file positioned low on the edge closest to you, and end up high on the edge furthest from you. Swipe several times.
Repeat Steps 2 and 3 on the opposite side of the blade. Continue back and forth between sides until you have the desired sharpness.
Repeat Steps 2 through 4 with a fine metal file to finely hone the blade and complete the sharpening process.