Install a temporary staircase in preparation for going up to the 2nd floor. Before going up to the 2nd floor, 2 floor slabs will be used to temporarily step on it, allowing people to go up to the top.
Install temporary stairs and prepare to go up to the second floor. Before going up to the second floor, two boards will be used for temporary treads, so people can go up.
Install temporary stairs and prepare the second floor. First, at the top. The second floor will use two floors as temporary pedals, so people will be allowed to go upstairs.