That is a first step, but is not sufficient on its own.
"You believe that there is one God. You do well. Even the demons believe--and tremble!" (James 2:19)
So while believing in God is a necessary prerequisite, merely believing in God does not mean you are saved. You must still repent and accept the sacrificial death of Christ as atonement for your sins, and make Him Lord of your life.
It is the starting foundation you have to consider. And yes you are correct that it has to go from there.