Win 7 BIOS settings for WD Blue SN550 NVMe

Hello:
I have a nice Optiplex 5040, i3-6100 64 bit Windows 7. My bios is current at Ver 1.14.5 and I think other drivers are up to date. The OS is on a Samsung 1TB SSD.

Last week I decided to upgrade(?) and add a WD Blue SN550 NVMe (WDS100T2B0C) SSD to use for the OS so I can backup everything internally on the old Samsung SSD with Acronis that will backup the entire computer. The only thing I’ve done with the drive so far is format and copy some music files on it to make sure it worked.

I realize to fully utilize the new SSD I need to make some bios changes with strange words like AHCI, UEFI, SATA and that makes me nervous. Tried searching Dell for info on changing the bios but found nothing. I guess the best way would be to change only one item at a time and reboot but how do I tell if it really made things better?

I did take some pictures of several bios screens that I could upload but basically I’ll list what is current. These were set with Dell support when I had support.

Boot List Option = Legacy
Advance Boot Options = Enable Legacy Option ROMs
UEFI Boot Path Security = Always except internal HDD
SATA Operation = RAID On
Under Drives I have SATA 0-4 listed then M.2 PCIe SSD-0 showing the new WDC disk

Thanks for any info on how to proceed.