Trying to create one-to-many relation in nopCommerce

I have created a new entity named NGO in nopCommerce. I am able to manage CURD operation of this entity. It means insert, update and delete is working for this entity. Now I want to make a relation of NGO entity with Order.

Like on order confirmation, I want to show a list of all available NGOs. Customer will select one or multiple NGOs and confirm the order. At the end, I want to know how many customers has selected which NGO while confirming the record.


Any clue how I can make a one-to-many NGO entity relation with Order entity.