- Will god help people who don't have knowledge about God but Believe in God?
Yes of course.Sri Krishna says in the Gita :
10.11 Out of compassion for them alone, I, residing in their hearts, destroy the darkness born of ignorance with the luminous lamp of Knowledge.
So God Himself will reveal the True Knowledge to them.
- Will God accept people who worship God according to their own faith/beliefs?
Yes. Sri Krishna says in the Gita:
4.11 According to the manner in which they approach Me, I favour them in that very manner. O son of Partha, human beings follow My path in every way.
Can a person deny a knowledge written in Religious books and begin worshiping god according to his own understanding. Will god help them?
No. Sri Krishna says in the Gita:
16.23 Ignoring the precept of the scriptures, he who acts under the impulsion of passion,-he does not attain perfection, nor happiness, nor the supreme Goal.
16.24 Therefore, the scripture is your authority as regards the determination of what is to be done and what is not to be done. After understanding (your) duty as presented by scriptural injunction, you ought to perform (your duty) here.
Hope these answers your queries.