If you are going to use it medicinally instead of food I would start by peeling the outside since they wax the roots. Then slice the inner root in to really thin slices so they can be spread out on wax paper or other clean surface and dried easily. Put it somewhere with good air flow since it really tends to hold on to water and can be hard to dry. You want to dry it as quick as possible though to prevent molding. This is why thin slicing helps. Once dried I would grind it in to a powder so you don't lose the fiber and use it like that, mixed in formulations, or capsules. If you want a real fine powder you can run the ground powder through a fine mesh screen then run the larger particles through the grinder again.