One test is to find out how this group views other Christians. Cults often claim that they, and they alone, have the truth about God, and they often dismiss other churches as wrong or misguided. They also may claim that God gave their founder a new revelation that "corrects" the "errors" of others.
Claims like this should be like an alarm bell to your soul. The Bible teaches that Jesus Christ was God in human flesh - and because of that, He was God's final word to the human race. Nothing needs to be added to Christ, the Bible says, because God's work of salvation is complete in Him. As the Bible says, in Christ "are hidden all the treasures of wisdom and knowledge" (Colossians 2:3). This is what Christians have held for 2,000 years, and it is central to our faith.
However, cults usually deny that Jesus was the unique Son of God, sent from heaven to save us from our sins. They also may add other books to the Bible, or substitute their own teachings for the Bible's truth. They also deny that our greatest need is to be cleansed of our sins, and that the only way this can happen is through faith and trust in Christ.
Don't be misled by this group's friendliness. Instead, turn to Christ and put your faith and hope in Him alone. Then ask God to guide you to a church that faithfully teaches the Bible, so you can grow in your relationship to Christ.