where to find Serial number?

Good day. I was given Insta360 GO as a gift a while ago. I have been having problems with downloading files to my computer. I was prompted to get an account and the first thing it asked me is to enter a serial number. When I plug my cam into the iPhone in settings I see the serial but when I try to enter it in this web site to get an account, it tells me it is wrong. I lost the case so I need to know where to get the serial number for my cam so I can try to download a controller for my mac and download videos with full res. I have been doing it to my iPhone but it is overly complicated and I have to do it one by one and the final res is really bad.Thank you for your help!

Juan