Filters on custom mongodb query

Can you please guide me how we can set variables in mongodb native queries?
you suggested me -
Try making a query in the GUI with a filter, and then convert to Native query. It's much easier to learn from looking at real examples.
So here I have attached a simple native converted query

[
  {
    "$match": {
      "$and": [
        {
          "linkedin_response.is_poi": true
        },
        {
          "linkedin_response.archive": false
        }
      ]
    }
  },
  {
    "$group": {
      "_id": {
        "created_at~~~week": {
          "$let": {
            "vars": {
              "parts": {
                "$dateToParts": {
                  "timezone": "GMT",
                  "date": {
                    "$subtract": [
                      "$created_at",
                      {
                        "$multiply": [
                          {
                            "$subtract": [
                              {
                                "$let": {
                                  "vars": {
                                    "day_of_week": {
                                      "$mod": [
                                        {
                                          "$add": [
                                            {
                                              "$dayOfWeek": "$created_at"
                                            },
                                            6
                                          ]
                                        },
                                        7
                                      ]
                                    }
                                  },
                                  "in": {
                                    "$cond": {
                                      "if": {
                                        "$eq": [
                                          "$day_of_week",
                                          0
                                        ]
                                      },
                                      "then": 7,
                                      "else": "$day_of_week"
                                    }
                                  }
                                }
                              },
                              1
                            ]
                          },
                          86400000
                        ]
                      }
                    ]
                  }
                }
              }
            },
            "in": {
              "$dateFromParts": {
                "timezone": "GMT",
                "year": "$parts.year",
                "month": "$parts.month",
                "day": "$parts.day"
              }
            }
          }
        }
      },
      "avg": {
        "$avg": "$total_score"
      }
    }
  },
  {
    "$sort": {
      "_id": 1
    }
  },
  {
    "$project": {
      "_id": false,
      "created_at~~~week": "$_id.created_at~~~week",
      "avg": true
    }
  },
  {
    "$sort": {
      "created_at~~~week": 1
    }
  }
]

please suggest me where I should put {{}} for making "created_at " variable. So that I can use it as a filter in my dashboards.

Diagnostic Info-
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"browser-info": {
"language": "en-GB",
"platform": "MacIntel",
"userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36",
"vendor": "Google Inc."
}
}

Hi @varnika
Have a look here: https://www.metabase.com/docs/latest/questions/native-editor/sql-parameters.html
Otherwise try searching the forum.