If your Wen compressor is brand new, you will need to follow the steps in the manual for installing the wheels, air filter, and oil cap breather. Once this is complete, or if it is already assembled, inspect the machine and make sure all parts are not damaged. check the pressure switch to ensure it is off and the tank drain valve is closed. Connect an air hose to the compressor that is suitably rated, connect the electrical plug to a power source, and turn the pressure switch on to allow the compressor to build pressure. Use the air compressor regulator to control the output of airflow of the compressor.