What? Start with praying. Share your 15-second testimony with each other. Then explain the gospel in the 3 circles. Read the Bible and ask them to accept Jesus as Lord.
Matthew 10:16-20 (KJV)
16 Behold, I send you forth as sheep in the midst of wolves: be ye therefore wise as serpents, and harmless as doves.
17 But beware of men: for they will deliver you up to the councils, and they will scourge you in their synagogues;
18 And ye shall be brought before governors and kings for my sake, for a testimony against them and the Gentiles.
19 But when they deliver you up, take no thought how or what ye shall speak: for it shall be given you in that same hour what ye shall speak.
20 For it is not ye that speak, but the Spirit of your Father which speaketh in you.