Yes, it’s supposed to update “content” in datacell_id 20, below i’ve pasted the full example from api’s documentation, i’m interested in “descriptions:…” part. I just dont know how to write the key in make’s input field. Simple values work fine when entering the key as text, but for arrays there may be another method - but i couldn’t find anything online 
{
“title”: “Produkt testowy”,
“catalog”: “1VWOCN48”,
“ean”: “7501031311309”,
“symbol”: “SYM123”,
“location”: “PS-32-3”,
“quantity”: 5,
“weight”: 1.5,
“as_set”: false,
“volume”: 1,
“no_barcode_label”: 1,
“price”: 153.22,
“price_promo”: 72.22,
“price_buy”: 153.22,
“promotion”: 1,
“presale_date”: “2023-04-13 12:00:59”,
“vat”: 23,
“status”: 1,
“category_id”: 1,
“variants_group_id”: 1,
“unit_id”: 1,
“availability_id”: 1,
“shipment_template_id”: 1,
“priority”: 1,
“step”: 0.001,
“alert”: 3,
“extra_info”: “Dodatkowe informacje”,
“bestseller”: 0,
“new”: 1,
“manufacturer_id”: 1,
“description”: “Spodnie sztruksowe zielone, bardzo ładne”,
“responsibleperson_id”: 123,
“description_short”: “Fajne spodnie”,
“descriptions”: [
{
“datacell_id”: 21,
“content”: “Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam vulputate condimentum mi eu bibendum. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.”
}
],
“meta”: {
“title”: “Meta tytuł”,
“keywords”: “Meta słowa kluczowe”,
“description”: “Meta description”
},
“images”: [
“https://sellingo.pl/public/themes/default/images/logo.png”,
“https://sellingo.pl/public/themes/default/images/logo.png”,
“https://sellingo.pl/public/themes/default/images/logo.png”
],
“categories”: [
5,
19,
24
],
“storages”: [
{
“id”: 1,
“storage_id”: 341,
“product_variant_id”: 7691,
“quantity”: 1,
“rack_id”: 232,
“shelf_id”: 1
}
],
“suppliers”: [
{
“quantity”: 1,
“supplier_id”: 5
}
],
“pricesfieldsvalues”: [
{
“id”: 1,
“pricesfield_id”: 2,
“value”: 21.9
}
],
“shops_settings”: [
{
“shop_id”: 1,
“price”: 33.99,
“price_promo”: 19.99,
“promotion”: 1,
“promotion_end”: “2023-04-13 12:00:59”
}
],
“additional_fields”: [
{
“field_id”: 1,
“field_name”: “pole_tekstowe”,
“field_value”: “wartość pola”
},
{
“field_id”: 3,
“field_name”: “checkbox”,
“field_value”: “tak”
},
{
“field_id”: 3,
“field_name”: “checkbox”,
“field_value”: “nie”
},
{
“field_id”: 4,
“field_name”: “Dodatkowe pliki”,
“field_value”: “base64”
}
],
“external_offers_settings”: [
{
“offer_id”: 8,
“external_account_id”: 2,
“price”: 52.99,
“price_promo”: 42.99,
“promotion”: 1,
“promotion_end”: “2023-04-13 12:00:59”
}
],
“external_shops_mappings”: [
{
“shop_id”: 8,
“foreign_id”: 2
}
]
}