The most common dosing scheme for dutasteride is to take 0.5mg each day. Some users go for a lower dose of 0.5mg every other day (equivalent to 0.25mg a day), or 0.5mg two days out of every three (equivalent to 0.33mg a day).
Don't use finasteride in addition to dutasteride. dutasteride does everything finasteride does and more, so using finasteride in addition is totally pointless.