Need shopify expert for multi vendor app

Hello, i have a shopify marketplace and use the app multi vendor app which is this:
https://apps.shopify.com/multi-vendor-marketplace?search_id=4c3a4cc0-ffa9-48b5-a710-289cc047a37d&surface_detail=multi+vendor+marketplace&surface_inter_position=1&surface_intra_position=4&surface_type=search

I need to know how to integrate the API for the seller to add their products