Hi I have reviewed your requirement, are you submitted the business detail to facebook and get approval and API key detail. Once you ready, then i am also ready to integrate the whatsapp business api.
Can you please explain the following things , do you need or not
1) Send message, media type : image, video, document
2) webhook : receive message from sender.
Please let me know, hat is the purpose of this task of business logic behind this. Do you want to give support to your customer.
I have 9 years of experience in PHP, Codeigniter, Yii and MySql
Please ping me on chat and mention you comfortable time to discuss the task list.
I will give you 6 month free support after finish the application.