But I don't understand " the nembutsu created the cause " ?
Can you explain more ?
Creating the cause meaning you secure your place in the pure land by saying the nembutsu according to the vows of Amitabha.
And who can I practice the nembutsu ?
Do i just say it . Or I have focus completely on it ?
You just need to say it with repetition. It's very simple and straightforward.
And how many nembutsu i have to say in the day ?
Whatever number you are most comfortable with. Honen advised that is good to have a set number of repetitions per day and to be as consistent as possible in order to accumulate merit for a successful rebirth in the pure land.
Thank you very much dear dharma friend .