Add a participant to to an existing conference using Conference Participant API in twilio php sdk in Laravel 9

I am trying to add a participant to an existing conference call using the Participant Resource API. I have first fetched the conference_sid in and then tried to add the new participant to the ongoing.

public function twilioConferenceCall2(Request $request) {
        $returnArray = array();
        $status = "Error";
        $msg = "Call not started";
        $validator = Validator::make($request->all(), [
            'participant' => 'required',
            'contact_id' => 'required'
        ]);
        if ($validator->fails()) {
            return response()->json(['error' => $validator->errors()], 401);
        }

        $participant = $request->input('participant');
        $contact_id = $request->input('contact_id');
        $sid = "aaaa";
        $token = "bbbb";
        $client = new Client($sid, $token);

        $conferences = $client->conferences->read(
            array("status" => "in-progress", "friendlyName" => "NewConference")
        );
        
        $conference_sid = $conferences->sid;
        $call = $client->conferences($conference_sid)
                        ->participants
                        ->create($participant);
}

The Twilio Documentation provide information about creating a new participant using Conference Participant API, but has not given details about how to add participants to an ongoing conference.

Kindly suggest is it correct to add a participant?