Salvation is a posture of repentance and faith toward the finished work of Christ in which you transfer the weight of your hopes of heaven off of your own righteousness and onto the finished work of Jesus Christ. The way to know you made the decision is by the fact you are resting in Christ now.
J. D. Greear, Stop Asking Jesus Into Your Heart: How to Know for Sure You Are Saved, (B & H, 2013), pg 43