insert various objects and match the existing collection mongoose and express

first question here..

first I want to explain my difficulty here please help me.

I'm studying mongodb, mongoose and express, my problem here is that I want to match the user database with the pelatihan database.

this is an example of the output that i already make ->

{
    "nama": "asep hernawan",
    "email": "asepsp71@gmail.com",
    "nomor_pendaftaran": "1141112197116",
    "tanggal-lahir": "11/12/1971",
    "images": "Source URL to IMAGE",
    "pelatihan":{

    }
    "tokens": [{
        "_id": """token": "(should be user token that im already know how to generate with JWT)"
    }]
}

so, here's the scheme ..

admin first enter the database for training, because training is indeed based on a schedule, and here the pelatihan database should look like

{
    "id": """nama_instansi": "akper_jakarta",
    "tanggal_pelatihan": "27/02/2020",
    "nama_pemimpin": "ibu. humairah",
    "jenis_pelatiihan": "btcls",
}

after that during the training the user will register on the Android platform, and fill the data in user data. what I want is that the user enters the data including kota_pelatihan, tanggal_pelatihan, and if the kota_pelatihan and tanggal_pelatihan are the same as in thetraining database the output will be like this ->

{
    "id": "",
    "nama": "asep hernawan",
    "email": "asepsp71@gmail.com",
    "nomor_pendaftaran": "1141112197116",
    "tanggal-lahir": "11/12/1971",
    "images": "PDF FILE URL",
    "pelatihan": {
        "id": "",
        "kota_pelatihan": "jakarta",
        "nama_tempat": "akper jakarta",
        "tanggal_pelatihan": "27/02/2020",
        "jenis_pelatihan": "btcls"
    },
    "tokens": [{
        "_id": "",
        "token": "TOKENS FROM JWT"
    }]
}

this is my current User schema in expreess ->

const userSchema = mongoose.Schema({
    nama: {
        type: String,
        required: true,
        trim: true
    },
    email: {
        type: String,
        required: true,
        unique: true,
        lowercase: true,
        validate: value => {
            if (!validator.isEmail(value)) {
                throw new Error({error: 'Invalid Email address'})
            }
        }
    },
    nomor_pendaftaran: {
        type: String,
        require: true
    },
    Images: {
        type: String,
        require: false
    },
    tanggal_lahir: {
        type: String,
        required: true,
    },
    logbook: {

    },
    sertifikat :{
        sertifikat_sos: Boolean,
        sertifikat_kementrian: Boolean,
        status: {
            dikemas: Boolean,
            dalam_perjalanan: Boolean,
            diterima: Boolean
        }
    },
    pelatihan: {
        nama_instansi: String,
        tanggal_pelatihan: String,
        jenis_pelatihan: String
    },
    tokens: [{
        token: {
            type: String,
            required: true
        }
    }]
});

I'm really just learning Mongoose, MongoBb and Express and this is a bit depressing. forgive me if my questions are complicated and forgive my english which is not fluent or good, cheers!