install an additional SSD internal to my ESC1250

Here you go... Step-by-Step BIOS  for ESC1250

1. Enter BIOS Setup
 Power on the ESC1250 and tap F2 repeatedly as soon as the Dell logo appears
 This opens the BIOS setup utility
 
2. Verify SSD Detection
 Navigate to System Information or Storage Configuration
 Confirm the new SATA SSD is listed under SATA Port 1/2/ or 3 (depending on where you plugged it)
 
3. Set SATA Mode (if needed)
 Go to Advanced → SATA Configuration
 Ensure "AHCI"  is selected (not RAID or IDE)
 AHCI ensures optimal SSD performance
 
4. Adjust Boot Order (Optional)
 If you want to boot from the new SSD:
  Go to Boot → Boot Priority
 Move the new SSD to the top of the list
 If the new drive is just for file storage and not for windows, leave boot order unchanged
 
5. Save and Exit
 Press F10 → Select Yes to save changes and reboot

After reboot -- on your desktop .. bottom left of your desktop type in the search box the word disk.. when the menu pops up look for disk management..thats where you want to go.  

 → once there Initialize and format the new SSD if it’s unallocated.. if you see the drive there with no drive letter right click on that space and select initialize. After that, you can format it (choose NTFS is best) and assign a drive letter.
 
If BIOS doesn’t detect the SSD: → Double-check SATA cable and power connection
→ Try a different SATA port