Fetal heart rate monitor

I got a wumic heart rate monitor. It says around 10 weeks women can start to hear their babies heart beat. I am 11 and a half weeks, pretty skinny and I still can't find it. I'm not that worried, but I was wondering where I should be using it. Around my hip towards my pelvis I heard swooshing noises, but it's only 64 bmp, so I'm sure that not the baby. Do you have any tips for me? B