Store OAuth access token for other requests

Hi, I'm developing a custom connector usint OAuth as my authentication method.
I'm able to authenticate but I would need to store the access_token for later use.
I need to make an api request to a resource but the requests header needs to contain the "x-approuter-authorization" = access token" parameter.

My code looks like this at the moment:

section PQExtension1;

client_id = "XXXXX"
client_secret = "XXXXXX"
redirect_uri = "https://...../oauthredirect"
token_uri = "https://...../token"
authorize_uri = "https://..../authorize"
logout_uri = "https://..../logout"

// Login modal window dimensions
windowWidth = 720;
windowHeight = 1024;

// OAuth2 scope
scope_prefix = "";
scopes = {
    XXXX,
    YYYY
};

[DataSource.Kind="PQExtension1", Publish="PQExtension1.Publish"]
shared PQExtension1.Contents = (url as text) =>
    let
        //authHeader = Text.Combine({"Bearer ", token}),
        source = Json.Document(Web.Contents(url))//, [Headers=[
               //#"x-approuter-authorization" = authHeader
           //]])
    in
        source;

// Data Source Kind description
PQExtension1= [
    TestConnection = (dataSourcePath) => { "PQExtension1.Contents", dataSourcePath },
    Authentication = [
        OAuth = [
            StartLogin=StartLogin,
            FinishLogin=FinishLogin,
            Refresh=Refresh,
            Logout=Logout
        ]
    ],
    Label = Extension.LoadString("DataSourceLabel")
];

// Data Source UI publishing description
PQExtension1.Publish = [
    Beta = true,
    Category = "Other",
    ButtonText = { Extension.LoadString("ButtonTitle"), Extension.LoadString("ButtonHelp") },
    LearnMoreUrl = "https://powerbi.microsoft.com/",
    SourceImage = PQExtension1.Icons,
    SourceTypeImage = PQExtension1.Icons
];

// Helper functions for OAuth2: StartLogin, FinishLogin, Refresh, Logout
StartLogin = (resourceUrl, state, display) =>
    let
        authorizeUrl = authorize_uri & "?" & Uri.BuildQueryString([
            response_type = "code",
            client_id = client_id,  
            redirect_uri = redirect_uri,
            state = state,
            scope = GetScopeString(scopes, scope_prefix)
        ])
    in
        [
            LoginUri = authorizeUrl,
            CallbackUri = redirect_uri,
            WindowHeight = 720,
            WindowWidth = 1024,
            Context = null
        ];

FinishLogin = (context, callbackUri, state) =>
    let
        // parse the full callbackUri, and extract the Query string
        parts = Uri.Parts(callbackUri)[Query],
        // if the query string contains an "error" field, raise an error
        // otherwise call TokenMethod to exchange our code for an access_token
        result = if (Record.HasFields(parts, {"error", "error_description"})) then 
                    error Error.Record(parts[error], parts[error_description], parts)
                 else
                    TokenMethod("authorization_code", "code", parts[code])
    in
        result;

Refresh = (resourceUrl, refresh_token) => TokenMethod("refresh_token", "refresh_token", refresh_token);

Logout = (token) => logout_uri;

TokenMethod = (grantType, tokenField, code) =>
    let
        queryString = [
            grant_type = "authorization_code",
            redirect_uri = redirect_uri,
            client_id = client_id,
            client_secret = client_secret
        ],
        queryWithCode = Record.AddField(queryString, tokenField, code),

        tokenResponse = Web.Contents(token_uri, [
            Content = Text.ToBinary(Uri.BuildQueryString(queryWithCode)),
            Headers = [
                #"Content-type" = "application/x-www-form-urlencoded",
                #"Accept" = "application/json"
            ],
            ManualStatusHandling = {400} 
        ]),
        body = Json.Document(tokenResponse),
        result = if (Record.HasFields(body, {"error", "error_description"})) then 
                    error Error.Record(body[error], body[error_description], body)
                 else
                    body
    in
        result;

Value.IfNull = (a, b) => if a <> null then a else b;

GetScopeString = (scopes as list, optional scopePrefix as text) as text =>
    let
        prefix = Value.IfNull(scopePrefix, ""),
        addPrefix = List.Transform(scopes, each prefix & _),
        asText = Text.Combine(addPrefix, " ")
    in
        asText;
        
PQExtension1.Icons = [
Icon16 = { Extension.Contents("PQExtension116.png"), Extension.Contents("PQExtension120.png"), Extension.Contents("PQExtension124.png"), Extension.Contents("PQExtension132.png") },
Icon32 = { Extension.Contents("PQExtension132.png"), Extension.Contents("PQExtension140.png"), Extension.Contents("PQExtension148.png"), Extension.Contents("PQExtension164.png") }
];

Any kind of help is much appreciated..