You go to their website - a simple google will find it, it's the top result:
clarifias API for face detection - Google Search[
^]
Then you talk to them and pay them money (no idea how much, but I suspect it's "if you have to ask, you can't afford it").
They then will provide you with what you need, and also give you technical support to help you use it.
Any other route would be illegal.
And ... in future, please remember that we have no access to your system: we cannot open a file on your local hard drive!