I need to know to GRIND DANCE (in detail)?

ok, so I have a school dance to go to & everyone is going to be grinding.I've been avoiding dances because of this for so long now but this time I told myself I should just go.Problem is, I cant grind.I already looked up answers on here & videos on youtube and none really helped.There are a lot of different things people say like puting your legs in between each others and others say you go down and all this stuff but, I never really heard that you should do that.I dont want to be laughed at or embaressed...I just want to have a good time...so, if someone could help me that would be great.