For individuals self-studying it is almost impossible to say. As all candidates have different experience and amount of time available for study, it varies from person to person. We suggest you buy the manual and have a look through for yourself before deciding how long you need to spend learning.
For those studying with an accredited training organization, Foundation courses are generally delivered over 3 days, while combined Foundation and Practitioner courses are generally delivered over 5 days. It is well worth investigating with individual providers, as some will offer tailored, online or blended learning solutions.