I want to learn how to sing...please help?

i used to be in a church choir when i was young (before puberty) i quit... why do i want to learn? because i see so many people have fun singing and sining in the car and shower and by my self i dont know it just feels relaxing and fun... please help i love Ariana Grande from Victorious.. i just want a good singing voice just to sing like rap or any music please help me...