Okay I realized that in the second question I wrote before, it would be enough to multiply the probability for a value of name_customers(in this case ‘JOHN’) and the probability for a value of id_customers(in the example I wrote, 13467780), which are independient.
Multiplying these two values I would get the probability that I am looking for the second question.
Anyway, apart from the official documentation, does anyone know any documentation that can help me to write the models and adjust my distributions as best as possible? Thankyou.