Power off the Lenovo M710s and unplug the power cable
Remove the side cover
Check for an available 2.5-inch or 3.5-inch drive bay
Check for an available SATA data port on the motherboard
Check for an available SATA power connector from the power supply
Mount the second drive in the empty bay
Connect the SATA data cable to the drive and motherboard
Connect the SATA power cable to the drive
Reinstall the side cover
Plug in the power cable and turn on the PC
Enter BIOS/UEFI setup during startup
Confirm the second drive is detected in storage settings
Save and exit BIOS/UEFI
Boot into Windows
Open Disk Management
Initialize the new drive if prompted
Create a new volume on the drive
Format the partition
Assign a drive letter
Verify the drive appears in File Explorer