Sending date from arduino code to firebase

Greetings all,

I am storing sensors data to firebase which is working fine but I want to add the time with each value.
I did a lot of research and I tried using json and other methods but nothing is working .
I get the time printing in the serial monitor but when I try to store it in firebase some methods give error or no error but the time wont upload .

The following is one of the codes I have been trying but its missing the lines to store date in firebase since that is my question.
I am using arduino wifi rev2 .
`
#include <WiFiNINA.h>
#include <Firebase_Arduino_WiFiNINA.h>
#include <Firebase_Arduino_WiFiNINA_HTTPClient.h>
#include <NTPClient.h>
#include <WiFiUdp.h>

#define FIREBASE_HOST "............"
#define FIREBASE_AUTH "................."
#define WIFI_SSID "......."
#define WIFI_PASSWORD "......."

const long utcOffsetInSeconds = 14400;

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP,utcOffsetInSeconds);

FirebaseData firebaseData;
bool state = false;
double currentTimestamp ;

void setup()
{

Serial.begin(115200);
delay(100);
Serial.println();
Serial.print("Connecting to Wi-Fi");
int status = WL_IDLE_STATUS;
while (status != WL_CONNECTED)
{
status = WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
Serial.print(".");
delay(300);
timeClient.begin();

}
Serial.println();
Serial.print("Connected with IP: ");

Serial.println(WiFi.localIP());
Serial.println();

//Provide the authentication data
Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH, WIFI_SSID, WIFI_PASSWORD);
Firebase.reconnectWiFi(true);

}

void loop()
{

//---------------------------------

timeClient.update();

/Serial.print(timeClient.getHours());
/Serial.print(":");
/Serial.print(timeClient.getMinutes());
/Serial.print(":");
/Serial.println(timeClient.getSeconds());

/String TimeNow = timeClient.getFormattedTime();
/ Serial.println(TimeNow);

}`

Show the code trying to append date, time....

Thank you for responding.
Just to let you know I am a beginner in this which probably show from the code, anyway these are some lines that i tried . I couldn't find the exact lines since I kept editing the code and changing thing multiple times but the following to give you an idea and if you let me know what I am doing wrong .

Firebase.setString(TimeNow);

Firebase.setJSON ()

I also tries using pushString which i don't know if it a thing .

Thanks. Sorry but I don't know the details of using Firebase, how it works.
You already manage to transfer a lot of data so adding date/time ought to be "not too difficult" as I thought.
What does the other transferring code look like?
Could You post the entire code?