Insert reference field by code

I just found the solution! I’ve kept the normal insert statement, but I changed the values of the dropdowns.
I queried the field “_id” of the collection Month (not month_id!) and Motif, and filled the values as value for the corresponding dropdowns. Now the array with the data to insert looks like that:

  1. “18”
    photoid:

  2. “Urs Luginbuehl”
    uploadedby:

  3. 2019
    year:

  4. " 6b3a0e41-46ea-4ce7-8364-eba92bbccdfe"
    month_id:

  5. “3ae3e4ca-72da-4f75-b626-75b8876c2346”
    motif_id:

  6. “Description”
    description:

  7. “image://v1/246733_b27a21ac571a48499482fe588099220a~mv2.jpg/1400_787/246733_b27a21ac571a48499482fe588099220a~mv2.jpg”
    photo:

  8. “50d1b71a-1d7c-444f-a397-d744ef5bc8eb”
    _id:

  9. “246733f0-e5a4-4235-bd27-11e9ca5a946b”
    _owner:

  10. “2020-01-16T14:32:20.794Z”
    _createdDate:

  11. “2020-01-16T14:32:20.795Z”
    _updatedDate:

[4] and [5] are referenced fields _id’s .

Perhaps you can explain the topic more clear than I.
But anyway thanks for trying to help us.