Would you please explain the following in bold more easily?
Once you are at the generation of the "to do" list, you simply transfer your action items to a 12-month calendar. I recommend using a 12-month calendar because many of your actions will be recurring (daily, weekly, monthly) and it helps to lay the whole thing out so you can see the path you have created. Once you have filled in the entire 12-month calendar with all your little goal babies, you will see that you have finally removed all the guesswork from life.
What is a 12-month calendar? Is it a calendar that all the 12 months are printed in one piece of paper? And what does "transfer" mean in the context?
In a paper-only context your definition is OK; but I suspect this is dealing with an online calendar. The action items are in your head. In setting up an online calendar you create an entry to represent each one. This is not really transferring it (because the idea stays in your head) - but that's what the writer means.