Mass messages using wsp api

Question

Good afternoon everyone, I am starting to use the WSP API for the first time and I would like to know how I can send mass messages using it. Since with the test number you give me you only let me send test messages to a single number, could u please help me. I use the API in POSTMAN

I was thinking about affiliating a real number and paying for the API, I don't know if that will solve it.