I did a Andersen slider on the second floor from the outside with my dad 20 years ago on his place in the north woods of Wisconsin...... on extension ladders and scaffolding because he was going to build a deck...... the deck never got built and the house sold with a slider on the 2nd floor. That was when I was younger and dumber than I am today.
have at least 1 other person to help you and the Admiral with the slider