Mongose ​​how to properly organize data sending schema?

Question

MongoDB

I have 2 collections of data. PRODUCT and ORDERS.
And they directly depend on each other , according to business logic. PRODUCT is what the business puts in the product list. And Orders is a list of orders . That is, orders are taken from PRODUCT. When I try to send an order with one request. Where two json strings are repeated. That is mongoose . Throws off only what is below . I highlighted this with a red line. How do I organize the ordering scheme like this. What would I order. Could send any number of products to the server?
-Nevertheless, I cannot
know how many products the business will eventually have.
Possible solutions I came up with...

On the front end, put everything in an array. And from there to get all the goods. Going through each, and sending. (crutch)

Draw a huge button for each order. Through which the order will be carried out. (crutch)