Download McEdit, open it, create a new world or open a level, on the bottom you will see a row of 9 options like in-game, select import, on mac drag and drop the schematic into the window it opened up, press choose, finally place where you want it! On windows i have no idea! Hope that helped!
try this video
hope it helps
Download it into the server file
//load schem <filename>
//paste
Its as simple as that.