Using populate() with Mongoose referencing child indices of a document

I am trying to return the first and last name of the user who created a document, as well as the one who last modified it. I am using populate()to do the JOIN between the two collections but it has not worked for me.

This is the area model

var mongo     = require('mongoose'),
    validator = require('mongoose-unique-validator'),
    Schema    = mongo.Schema


var model = new Schema({
    NAME:       { type: String, required: true, unique: true, max: 50, min: 3 },
    STATUS:     { type: String, default: 'active' },
    ADDED_BY:   { type: Schema.Types.ObjectId, ref: 'users' },
    ADDED_DATE: { type: Date, default: Date.now },
    MODIFY_BACKLOG :[{
        USER:     { type: Schema.Types.ObjectId, ref:'users' },
        DATE:     { type: Date, default: Date.now },
        CURRENT:  { type: String },
        MODIFIED: { type: String }
    }]


}, {collection :'areas'})

model.plugin( validator, { message: 'The {PATH} is not valid or duplicated' } )
module.exports = mongo.model('Area', model )

As you can see the indexes ADDED_BYand MODIFY_BACKLOG.USERthey are referring to the collection users.

This is the users model

var mongo     = require('mongoose'),
    validator = require('mongoose-unique-validator'),
    Schema = mongo.Schema

var userSchema = new Schema({
    PERSONAL_DATA: {
        NAME:            { type: String, required: [ true, 'The name is necessary' ], max: 50 },
        LAST_NAME:       { type: String, required: [ true, 'the lastname is necessary' ], max: 100 },
        PHOTO:           { type: String, max: 100 },
        BIRTHDAY:        { type: Date },
        MARITIAL_STATUS: { type: Schema.Types.ObjectId, ref: 'maritial_statuses' },
        GENDER:          { type: String, max: 1 },
        EMAIL:           { type: String, required: true  },
    },
    COMPANY_DATA: {
        JOB:      { type: Schema.Types.ObjectId, ref: 'jobs' },
        AREA:     { type: Schema.Types.ObjectId, ref: 'areas' },
        ROLE:     { type: Schema.Types.ObjectId, ref: 'roles' },
        BOSS:     { type: Schema.Types.ObjectId, ref: 'users' },
    }
}, { collection: 'users' } )

model.plugin( validator, { message: 'The {PATH} is not valid or duplicated' } )

module.exports = mongo.model('User', userSchema )

As the information is very robust in this model, I decided to separate it into PERSONAL_DATA, COMPANY_DATAand there are two other indices PAYMENT_DATA, ENGINE_DATA, each of these keeps indices that refer to the name of the father, but those do not interest me because they have nothing to do with the question and it is a model of approx. . 300 lines.

Inside COMPANY_DATA.AREAis where the area where the user belongs is included, I don't think it's relevant to this problem, but just in case.

This is the path consumed by the area model

var express = require('express'),
    Areas   = require('../../models/catalogs/areas'),
    app     = express()

app.get('/:from', (req, res) => {

    var from = parseInt( req.params.from )
    var populate = { 
        path: 'users', 
        select: 'NAME LAST_NAME'
    }
    Areas.find()
        .sort('NAME').populate( populate )
        .limit(10).skip(from)
        .exec((error, data) => {
            if (error) {
                return res.status(500).json({
                    success: false,
                    error
                })
            }

            Areas.count({}, ( err, total ) => {
                res.status(200).json({
                    success: true,
                    data,
                    total
                })
            })
            
        })
})

module.exports = app

populate()I am passing a variable with the same name to the method , where I am making the reference to the collection and what data I need from the user. This is where I am stuck because it is not bringing me the information of the user, it only brings me the information of the area and here I have three questions

How can I make the JOIN of the collections respect me?

How can I tell it that the indexes I need are not explicitly at the top level of the document, but inside PERSONAL_DATA? i tried with

var populate = { 
        path: 'users', 
        select: 'PERSONAL_DATA.NAME PERSONAL_DATA.LAST_NAME'
    }

But it's still the same, finally

The index MODIFY_BACKLOGin the area model also has the ObjectId of the user who made the modification, how can I say that the JOIN to users is also done to that index?

I leave an example of the answer

{
    "success": true,
    "data": [{
        "STATUS": "active",
        "_id": "5c547f4adadf433914f72c8c",
        "NAME": "Contabilidad y Finanzas",
        "ADDED_BY": "5c4f562deec6f4defeea759b",
        "ADDED_DATE": "2019-02-01T17:18:02.680Z",
        "__v": 0,
        "MODIFY_BACKLOG": []
    }, {
        "STATUS": "active",
        "_id": "5c645f476491cf093c51c38e",
        "NAME": "Recursos Humanos",
        "ADDED_BY": "5c4f562deec6f4defeea759b",
        "ADDED_DATE": "2019-02-13T18:17:43.036Z",
        "__v": 0,
        "MODIFY_BACKLOG": [{
            "DATE": "2019-02-13T19:43:18.273Z",
            "_id": "5c6473561370462754939107",
            "USER": "5c4f562deec6f4defeea759b",
            "CURRENT": "active",
            "MODIFIED": "{\"STATUS\":\"inactive\"}"
        }, {
            "DATE": "2019-02-13T19:43:24.213Z",
            "_id": "5c64735c1370462754939108",
            "USER": "5c4f562deec6f4defeea759b",
            "CURRENT": "inactive",
            "MODIFIED": "{\"STATUS\":\"active\"}"
        }]
    }],
    "total": 5
}