New to building computers and need some help

So I'm a long Mac user moving to Windows and building a computer and Windows is really foreign to me and I need some help. I can get my computer started but I can't load into bios and when I try installing windows it wont recognize my ssd drive in the M.2 slot. I'm kind of at a loss at what to do.

I know that your supposed to use F2 to enter bios at start up but the computer just keeps asking for a boot drive. I've tried booting from the dvd included with the motherboard but it just asks for me to enter a date and time and then give me a C prompt.

The motherboard I'm using is a B550m pro4, the cpu is a Ryzen 5 3600, 16gb DDR4 3000 Aegis memory, RX580 graphics. WD blue 500gb SSD, 2TB Seagate HDD.

I can't boot from the Seagate because that has all the files from my old Mac: saved games, music, movies, etc.

So any advice going forward here would be really appreciated.

Your M.2 form factor SSD is a SATA drive and will only work in the lower secondary slot on the motherboard. However according to the specifications this motherboard only supports booting from NVME drives and not SATA drives in the M.2 slot. So to boot the system you need to buy anew NVME type drive rather then SATA. I hope you can still return the drive you bought and use that money to get a new NVME M.2 drive. SATA M.2's are these days primarily made for external use in a USB enclosure or for older boards that only supported SATA trough the M:2 interface. Thse days in modern systems you are primarily supposed to run NVME drives in the M.2 slots. They are slightly more expensive but only slightly but have many times faster sequential write and read speeds for larger files. In regular daily operation for most users though a SATA SSD drive will feel almost as fast as a NVME drive.