What is the model number of the refrigerator?
If the noise was a metallic sound there may be a problem with one of the moving parts e.g. a fan, ice maker? or the compressor.
You may have to keep a check and listen if it happens again (you said that you only heard it the one time, is this correct?).
As the refrigerator is less than 12 months old it will still be covered by the manufacturer’s warranty. If it happens again or occurs more frequently contact the manufacturer’s customer service section for your location and get it checked out under warranty.
Worst case is if it is the compressor as this is the most expensive part but with most refrigerators there is a 5 year warranty on the compressor and sealed system. Check what the warranty provisions are for your refrigerator to see what is covered before and after the 1st year. The warranty can usually be found in the user manual that should have come with the refrigerator