Create a Sample Bubble.io Page with API Integration

Background : I have running an App with [login to view URL], recently i need to integrate 2 API with my bubble apps, but i have no idea how. I need an experienced [login to view URL] & API Integration Developer to help us create a Sample Page in Bubble with following : 1) Lalamove API Integration (Delivery Platform) Doc : [login to view URL] 2) Billplz API Integration (Payment Gateway) Doc :[login to view URL] ( I manage to call and authenticate, but i have no idea how to do the X Signature Call Back , after payment success ) Project: Just a Bubble Sample page, that able to integrate 2 api above ( with 1 sample call, create bill, or create quotation enough, i can do the rest once i understand from the sample page ) Sandbox API key will be provided.