In order to begin the trip to Machu Picchu, you should be aware that all routes start in Cusco, the navel of the world, which is the first stop to the Inca citadel. The most preferred means is to go by plane; the flight takes about an hour.
Then, you must go to the Aguas Calientes town, also known as Machu Picchu pueblo. It lies at the foot of the Machu Picchu Mountain and it is the last stop to enter the citadel. From there you may choose to go by bus, which takes about 25 minutes, or walk.
There are mainly two ways to get to Aguas Calientes.
The first and most common way is to take a train from the Poroy or Ollantaytambo stations. The Poroy station is 25 minutes away by car from Cusco’s Main Square, and the Ollantaytambo station is 1h 30 minutes away by car from Cusco. The journey to Machu Picchu lasts about 3h and 1h 40, respectively. Be aware that during the rainy season (from January to April), the Poroy station is closed for safety precautions.
The second way is to walk. Currently, there is a tour called "The Inca Trail", which are the roads that the people of the Inca Empire used. It starts at Km 82, near the Ollantaytambo station. You must take a bus or private car from Cusco to get there. The journey lasts approximately 4 days and 3 nights and requires a certain physical condition, since it is a road through the mountains that reaches up to 4,200 masl.