You will need 7zip to extract the file click here if you dont have 7zip and choose the one you need
If youre on windows click the start button and do these following steps
1.Type in %appdata% and hit enter 
2.Click .minecraft
3.Find and click Saves folder
4.Drag the extracted file into the Saves folder 
5.Youre done! Open minecraft then Single player and click on the world
Just a note when you are on the portal area jump out of the minecart and go in the portal the minecart should go in the nether portal then hop back in the minecart and ENJOY!