Hi @mauraulucien - the 2 easiest ways to play minor are 3rd position, as other folks have mentioned, or to buy a Natural Minor harmonica which are tuned to pay 2nd position and sound minor.
If the backing track is on YouTube, please provide a link and that would help to to tell you which of these options would likely sound better.
As @BnT mentioned, you can play minor on a standard harp in 2nd position, but this requires really good control of the -3’ bend and so is a bit challenging.
As @argold57 mentioned it’s very easy to figure out what harp you need for 3rd position, just up one letter name, so your C harmonica is good for Dm. Here’s the scales:
That quote comes fro this post:
By contrast, here’s a post showing what the Natural Minor harmonic sounds like: