Select the cell(s) or range you want to lock
Press Ctrl + 1 to open Format Cells
Go to the Protection tab
Check Locked
Click OK
Select the entire sheet (click the Select All button or press Ctrl + A)
Press Ctrl + 1
Go to the Protection tab
Uncheck Locked
Click OK
Re-select the cell(s) or range you want to lock
Press Ctrl + 1
Go to the Protection tab
Check Locked
Click OK
Review tab
Click Protect Sheet
(Optional) Set a password
Ensure Allow all users of this worksheet to: options are set as needed
Click OK
Save the workbook