Help needed can I replace the case where the battery goes? so I can use a spare battery while the others charging

Hi, I'm very new to having a ring doorbell. I bought a battery video doorbell 2nd generation last week, I was told that I could buy an extra battery so I can put that in when the other one is charging. So that's what I did but it doesn't go in as shown on the video? The silver outside cover of the doorbell has 8 little hex screws in the back. Can I buy a new case cover so I can just take it off so when the battery runs low I can just put the spare battery i brought in? Thank you