How to accept custom payments

Hi,

I have developed a custom booking from with php and javascript. Now I want to get payments at the end of this form. There will be different total amount for every booking process as the form has different options with variable price. So how can I get payment through this plugin. Definitely, there will be some custom coding in it. So if you can guide me which hooks or classes do I need to target, then it will be very helpful for me. If it works for me, I will definitely go for paid version. Thank you.