How to submit via api?

Hi, Thank for your help about install domjudge. Now it work ok and I want to submit problem via api.

/domjudge/api/submissions http://dj5.cachhoc.net/domjudge/api/submissions (POST) I read the document api but I can not know how to use it. I want use php to post submission, and now I test on postman but don't know what are fields to post data.