Need help API with refresh token

I wrote this script:

let
    #"HR-On employees" = let
    // Parametre
    client_id = "xxx",
    client_secret = "yyy",
    api_url = "url",
    token_url = "token",

    // Obtain Authorization Credentials
    ObtainAuthorizationCredentials = Json.Document(
        Web.Contents(token_url,
            [
                Content = Text.ToBinary("grant_type=client_credentials&client_id=" & client_id & "&client_secret=" & client_secret),
                Headers = [#"Content-Type" = "application/x-www-form-urlencoded"]
            ]
        )
    ),

    refresh_token = ObtainAuthorizationCredentials[refresh_token],

    access_token = ObtainAuthorizationCredentials[access_token],

    // Brug token til at hente data
    Kilde = Json.Document(
        Web.Contents(
            api_url,
            [
                Headers = [Authorization = "Bearer " & access_token]
            ]
        )
    ),
    items = Kilde[items]
in
    Kilde,
    items = #"HR-On employees"[items],
    #"Konverteret til tabel" = Table.FromList(items, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Udvidet Column1" = Table.ExpandRecordColumn(#"Konverteret til tabel", "Column1", {"id", "companyAdmin", "leader", "systemUser", "archived", "picture", "systemFields", "customFields", "departments", "roles", "createdAt", "updatedAt", "customId"}, {"id", "companyAdmin", "leader", "systemUser", "archived", "picture", "systemFields", "customFields", "departments", "roles", "createdAt", "updatedAt", "customId"})
in
    #"Udvidet Column1"

And now I get the data.