How can I properly install a deck stair stringer to ensure the stability and safety of my deck stairs?

To properly install a deck stair stringer for stability and safety, ensure it is securely attached to the deck frame using appropriate fasteners, such as screws or bolts. Use a level to ensure the stringer is plumb and straight, and add additional support with blocking or brackets if needed. Finally, attach the stair treads securely to the stringer to complete the installation.