The buildings on the other side of the main staircase are known as the Royal Palace, because it is here that the Inca and his family lived while visiting Machu Picchu [1]. There are a few beautiful trapezoidal doorways and perfect Inca stonework, both tell-tale signs of royal architecture. Follow the doorways and staircases to a large stone patio.
On the right-hand side of the patio there is a large fine door that is presumed to be the entrance to an area where the Inca slept. There are a few other rooms that the Inca and his family used for different purposes.
Climb to the top of the main staircase and turn right before the quarry. Continue about 60 meters to the botanical garden, where you may see various species of native flora. There are orchids, passion fruit trees, and a coca plant.
Beyond the garden to the left is the Sacred Square, containing both the Temple of the Three Windows [2] and the Principal Temple [3].
Links:
[1] http://www.moon.com/destinations/peru/machu-picchu
[2] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/sacred-square
[3] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/principal-temple