Convert data from spreadsheets to nested json - node.js

Question

I'm using mongodb in my project. And I'll import about 20,000 products to the database in the end. So, I tried to write a script to convert the data from the spreadsheet to json, and then upload them to the mongodb. But many fields were missing.
I'm trying to figure out how to layout the spreadsheet so it would contain nested data. But I didn't find any resources to do so but only this package:
https://www.npmjs.com/package/spread-sheet-to-nested-json
But it has one problem, it will always contain "title" and "children", not the actual name of the field.
This is my product json:
[
{
"sku": "ADX112",
"name": {
"en": "Multi-Mat Gallery Frames",
"ar": "لوحة بإطار"
},
"brand": "Dummy brand",
"description": {
"en": "Metal frame in a Black powder-coated finish. Tempered glass. 2 removable, acid-free paper mats included with each frame. Can be hung vertically and horizontally. D-rings included. 5x7 and 8x10 frames include easel backs. Sold individually. Made in China.",
"ar": "إطار اسود. صنع في الصين."
},
"tags": [
"art",
"frame",
"لوحة",
"إطار"
],
"colors": [
"#000000"
],
"dimensions": [
"5x7",
"8x10"
],
"units_in_stock": {
"5x7": 5,
"8x10": 7
},
"thumbnail": "https://via.placeholder.com/150",
"images": [
"https://via.placeholder.com/150",
"https://via.placeholder.com/150"
],
"unit_size": {
"en": [
"individual",
"set of 3"
],
"ar": [
"فردي",
"مجموعة من 3"
]
},
"unit_price": 2000,
"discount": 19,
"category_id": "631f3ca65b2310473b978ab5",
"subCategories_ids": [
"631f3ca65b2310473b978ab5",
"631f3ca65b2310473b978ab5"
],
"featured": false
}
]
How can I layout a spreadsheet so it would be a template for future imports?