There is only one living and true God. In the unity of the Godhead there are three persons. The Father, The Son, The Holy Ghost. They are equal in every divine perfection executing the office of the great work of redemption.
God the Son
Jesus. Born of a virgin Mary. He never sinned. He was crucified on the cross in our place. The Just died for the unjust. He was buried in a borrowed tomb, and rose again on the third day! He's alive! He's coming back!
God the Holy Ghost
Equal with the Father and the Son. Active in creation. He restrains evil until the Father's purpose is fulfilled. He convicts, seals, comforts, guides, teaches and helps believers.
He is real. He is a created being. He fell from heaven drawing after him a third of the angels. He is the prince of the power of the air. He can do nothing without God's okay. He's on a leash. He is man's greatest tempter and accuser. He is destined for defeat at the 2nd coming of Christ.
Comes by faith alone. We repent of our sins in humility and turn toward Christ by faith and only by faith. Christ died for all mankind, not a select group of people. Anyone can come to Christ by faith and have all sins forgiven regardless of their past!
Once you are truly saved, you're saved forever. We don't fall from grace when we sin, we fall into grace. We committed no works to receive salvation, we do no works that cancels our salvation. However, true believers live for Jesus forever!