Your article here: https://www.gardeningknowhow.com/edible/herbs/asafetida/asafetida-plant-information.htm describes how to grow asafetida. But would you know where to get seeds? I have looked extensively and have not found anyone who sells them.
We don't provide this kind of info, only free gardening how-to articles. You might search online for seed savers sites or ask at your local nurseries where to get some. I would avoid buying from individuals on auction-style websites because there are a lot of scammers selling so called "seeds."