After you complete your code, you need to compel the code and you need to upload it. To compel, you need to click on the ‘✓’ symbol and to dump the code, you need to click on the ‘→’ symbol. You need not compel the code before dumping, but it is better to compel before you code.The above mentioned symbols are present according to the picture shown.
Com port is the short cut for communication port. It is the port through which communication is done. We upload code written in Arduino IDE to Arduino board via Com port.
Selection of com port:
We need to go to tools -> Port to select required Com port.