Arduino DHT22 Sensor Problems

Hi, im new in coding and im trying for days now to solve this problem. I want a Arduino Uno with the DHT22 Temp. and Hum. Sensor and a OLED 128x64 Display. The Arduino is already put together and the code is as good as finished. Only one Problem:

#include <Adafruit_SSD1306.h> //Bibliothek 1
#include <Adafruit_GFX.h> //Bibliothek 2
#include <dht.h> //Bibliothek 3

#define dataPin 2. //Festlegung für Daten Pin
dht DHT;
#define OLED_RESET -1 //Reset Knopf Funktion
#define SCREEN_WIDTH 128 //OLED Display Höhe
#define SCREEN_HEIGHT 64 //OLED Display Breite
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, OLED_RESET);

void setup() { //Verzögerung Abbildung OLED
display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //Beginn Abbildung
delay(1000); //Delay 1 sek.
display.clearDisplay();
display.setTextSize(1); //Textgröße 1
display.setTextColor(WHITE); //Textfarbe Weiß
display.setCursor(0, 0); //Display 0 Punkt
display.print(“Temperature/Humidity”); //Hochfahr Sequenz Text
display.display();
Serial.begin(9600);
}
void loop() {
int readData = DHT.read22(dataPin); //Daten Pin für Info Übermittlung
float t = DHT.temperature; //Wert für Temperatur
float h = DHT.humidity; //Wert für Luftfeuchtigkeit

// Werte Print auf OLED-Display
Serial.print("Temperature = “);
Serial.print(t);
Serial.print(” *C “);
Serial.print(” Humidity = “);
Serial.print(h);
Serial.println(” % ");

delay(2000); // 2 Sekunden Verzögerung bis Neuanfang Loop
}

The error is:
Arduino: 1.8.13 Hourly Build 2020/06/16 12:33 (Windows 10), Board: “Arduino Uno”
sketch_Temp._FERTIG:9:1: error: ‘dht’ does not name a type

dht DHT;

^~~
C:\Users\Alexo\Documents\Arduino\radix_sketch_Temp._FERTIG\sketch_Temp._FERTIG.ino: In function ‘void loop()’:

sketch_Temp._FERTIG:28:21: error: expected primary-expression before ‘.’ token

int readData = DHT.read22(dataPin); //Daten Pin für Info Übermittlung

^
sketch_Temp._FERTIG:29:16: error: expected primary-expression before ‘.’ token

float t = DHT.temperature; //Wert für Temperatur

^
sketch_Temp._FERTIG:30:16: error: expected primary-expression before ‘.’ token

float h = DHT.humidity; //Wert für Luftfeuchtigkeit

^

Mehrere Bibliotheken wurden für “Adafruit_SSD1306.h” gefunden

Benutzt: C:\Users\Alexo\Documents\Arduino\libraries\Adafruit_SSD1306

Nicht benutzt: C:\Users\Alexo\Documents\Arduino\libraries\Adafruit_SSD1306_Wemos_Mini_OLED

exit status 1

‘dht’ does not name a type

Can somebody help? xD
ps… Sorry for the german comments on the side of the code. Thx for helping

Try compiling an example dht sketch from the dht library. It's probably not installed correctly.

honestly i dont know how to do that. I tried to find a video for explaining but i just dont know how to go on from here

The dht library I have uses:

#include "DHT.h";
DHT dht(DHTPIN, DHTTYPE);

case matters.