Hi jaydekaye, welcome to CC!
In order to understand how and why one goes to heaven or hell is essential when trying to understand it yourself, let alone explain it to your kids.
Here are some verses:
Romans 3:23
for all have sinned and fall short of the glory of God,
Romans 6:23
For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.
The Bible teaches we are sinners worthy of death and judgement for our wrongs. God however, in his mercy, provides a way to avoid judgement (hell). By his son Jesus' substitutionary death on the cross, Jesus took God's just wrath upon himself. If we count on Jesus' sacrifice to justify us before God, then we become pardoned and gain the free gift of salvation. At this point we cross over from death to life (MT 5:24) and surely will dwell with God in Paradise (heaven).
There is only one way: Jesus
(John 14:6)