Hi Martin,
Welcome to Christ! The word "Christ" means simply "anointed one" -- so to be a Christian simply means that "you've been anointed by God" to do as Christ did. And what did Christ do? Well, John 4:34 best answers this question. It is recorded that Jesus said: "My food is to do the will of Him who sent me." And this, Martin, must be your food as well.
Jesus obeyed the Father -- even unto death -- and he loved his neighbor as he loved himself (Mark 12:30-31). He preached the gospel to his neighbors (Mark 16:15), he forgave his neighbor's debts (Luke 6:37), and he loved his enemies -- doing good to those who mistreated him (Luke 6:28). Since a slave is not greater than his master, you must likewise do these things. Ask God to fill you with his Holy Spirit each morning -- for the Spirit is your teacher, comforter and helper. In a nutshell, that's what "it means to be a Christian." Does that make sense?
One thing is for certain: Christianity is not a "social club." The world loves to try new things and they bore easily. But as ambassadors for Christ, we are commanded to bring "good news" to the lost, boldly proclaiming the gospel -- in truth and in love -- to everyone we meet (2 Corinthians 5:20). Yet sadly, some Christians never share the gospel -- arguing that faith is a private matter, not to be discussed openly with others. But let me ask you this: "Have you ever heard of a silent ambassador?"
God richly bless you, Martin! I pray that Revelation 3:20 be made real in your life. For without Jesus, you can do nothing (John 15:15).
Hope this is helpful,
~Linette