Final answer:
To prevent unwanted changes in a worksheet, you should lock the cells containing text or formulas. This is done before protecting the sheet to enforce the locking mechanism.
Step-by-step explanation:
When building a worksheet for novice users, you should lock the cells in the worksheet that you do not want changed, such as cells that contain text or formulas. Locking cells is a feature available in spreadsheet programs like Microsoft Excel. It helps to prevent accidental editing or deletion of important information. Typically, you would first lock the cells and then protect the sheet, which enforces the lock and requires a password to make any changes to the locked cells.