Trying to get jiggy & learn dancing... HELP ME PLZ

Im trying to get into dancing... I am currently trying to lean the moves for ,"Not Cute Anymore" By ILLIT. It appears to be an easy dance....However, I'm having an insanely difficult time. Every move I make is stiff and just looks....bad....so very bad.... Are there any dancers out there that can give me advice? How do I get over the stiffness? I know part of the solution is to just dance more. But I feel like there's other stuff I can do to achieve this.... Please help me out!! :( 

-With Love and Stiffness, Murphy