Sending Variables to esp async web server

I'm trying to send 3 variables "Red,Green,Blue" to my asyncwebserver on arduino. Pretty sure the problem is on my esp32 server end and i have been searching for like 2 weeks ( barely novice programming skills ). I'm just looking for help on what should go in the space of my code or if I am going about it the wrong way.

RGBLED.aia (857.6 KB)

the part of the arduino code i'm not sure on is:

server.on("/RGBValue",HTTP_GET, (AsyncWebServerRequest *request) {

request->send(200, "application/json", webpage);


what goes in the middle to send the values from the app to the server again or if i'm going the totally wrong and difficult way thanx in advance