Help needed 🙏

Hi guys,

I’m trying to run Sonoma on my Mac Mini late 2014 but it isn’t recognising the boot drive. I have downloaded the operating system to my mac and the installer to my flash drive. It fails to go into boot when I restart pressing the option key. I have started in recovery and managed to restart into the boot menu from there but it doesn’t have any flash drive or OCLP options. Have I missed something?