Let's grab our DHT11 a temperature sensor!
For this sensor there's a library that can help you keeping things simple and the code clean.
Go ahead and grab the SimpleDHT library from the library manager, going into Sketch -> Include Library -> Manage Libraries and searching for it. Now that you've downloaded the library, it is available for you to use.
For starters, you have to create an instance of SimpleDHT11 and make it global by writing this outside any function
It is crucial to make it global so you can acess it no matter what function you're on, like void setup() or void loop() or any other.
#include <SimpleDHT.h>
int pinDHT11 = D0;
SimpleDHT11 dht11;
Everytime you want to read from the sensor you have to call this function specifying two variables in which you'll store the measurements:
byte temperature = 0;
byte humidity = 0;
dht11.read(pinDHT11, &temperature, &humidity, NULL);
delay(2000);
Then you can use those two variables.
Go ahead and make it print those values onto the Serial Monitor (remember to convert to integers before printing) and later on in webpages... You'll get there!
Ready? Let's move!