Help with payments and calendar

Building an ERP for my ERP in devellopment. I can do a lot myself, but payment methods(icw shopping cart) i dont know enough about, and making a good integration with google calendar is also over my top of knowledge. Who can help me, i am willing to pay a market conform price. I want it to be in PHPRunner in my style well integrated in my ERP. Besides i want to be able to take over management and maintenance... So learning is also a very important goal here. Please let me know! With the present closure of frontiers during Corona, it would be an advantage if you live in Holland. Though videoconferencing is ok, sometimes its better to meet.

Regards, Mark