Struggling to find baby’s heartbeat

I have an at home Doppler & I used to know what her heartbeat sounded like when I was like 8 weeks but once i got to 20 weeks I started to hear so many noises that I got confused & im still confused & im now 29 weeks , any tips ? because I know it’s suppose to sound fast but there are a lot of noises .. I even hear fast ones so it’s kind of hard so I try to listen out & feel for her movements so I can get a better idea but sometimes she’s stubborn & doesn’t move so any tips ? 😂