Follow this Simple Instruction:
First of all, one must believe in the Lord Jesus Christ (John 6:28-29), then repent (i.e. to turn from sin, and turn to God), be baptised (i.e. to be immersed in water – Romans 6:3-4), and receive the Gift of the Holy Spirit. (see: Acts 2:38). You will immediately speak in tongues. (Acts 2v4, Acts 10v44-46).