The basics about Christianity is that
1. God is sinless and lives in a sinless environment (Heaven)
2. Mankind is a sinful (commits wrong)
3. God loves man and desires mankind to live with Him forever.
4. Mankind is unable because of being sinful to live with a sinless God and stands guilty before Him
5. Mankind needed someone who could him or her acceptable to God.
6. Jesus the son of God lived a sinless life according to God's law and had the sin of the whole world placed on him when he died on the cross being a substitute payment in our place.
7. God was satisfied with what His Son did and raised Him from the dead signifying Jesus death was sufficient.
8. God by grace (unmerited favor) offers the free gift of salvation if humans are willing acknowledge their sinfulness before God and accept that by trusting that Jesus died on the cross in their place and rose again for them, God will cleanse them of their sins and declare them to have right standing with Him.
9. Those who put are trust in Christ to save them then are instructed to follow what God has laid out in the Bible including serving God out of gratitude and telling others about the Gospel (good news).