Hi [NAME]​ thank you for sharing update.  At Alienware splash screen, press and hold down the F2 key to enter BIOS/UEFI menu. On Main tab look for acknowledgement that the additional SSD is included on drive list and thereby confirm it has been installed correctly.  Then enter windows operating system and open Disk Management to see that additional SSD wants letter designation. Right click on Disk 1 to get menu, click on format and then assign drive letter to the SSD partition so that Windows can open the additional SSD.  How to manage storage devices on Windows 11 | Windows Central. 
I only have very basic computer skills. I was trying to expand storage with a PCIe M2 2280 SSD on my Alienware M17 R3. I found a video on how to open the back of the laptop and plug it in, so I did that, closed it back up and turned the computer on. I assumed this process would be like plugging in an external drive…I could just access it from windows like normal. But on boot up, an Alienware supportassist white screen came up. It says: Warning message  real time clock error system CMOS checksum bad time-of-day not set - please run SETUP program  I wasn’t expecting this and I’m not sure what to do. I really don’t want to screw up my computer. I did back it all up a couple weeks ago but really hoping I don’t have to do any restoring…is this a simple thing to work through? The options on buttons on the bottom of the  page read  continue     BIOS Setup     Diagnostics
m17 R3, help trying to expand storage with a PCIe M2 2280 SSD