Please refer the models shown below for instructions.

Introduction to Arduino
Interfacing of Rain drop sensor
Interfacing of Sound sensor
Interfacing of Double channel relay
Interfacing of OLED
Automatic Door Lock system
Display Scrolling Text on LED Matrix
Automatic Rain Detector
Sound Level and Intensity Measurement
Spectrum Analyzer
Water Flow and Volume Measurement
Interfacing of Flex Sensor
Pollution Detector
Earthquake Detector
Automatic Street Light Control
ECG display using Pulse sensor
Interfacing of Servo motor
Interfacing of LDR
Interfacing of Accelerometer
Interfacing of MQ135
Interfacing of 8*8 matrix
Interfacing of Pulse sensor