I am new in this world of Raspbian. I just bought a Raspberry Pi 3 model B with a power source with an output of 5 V 2500 mA. So I get one of my SD cards of 16 GB, I have download the .iso image of the Raspbian system from here and finally a software called Etcher that turned very easy to put the image in the SD. So I flashed the SD card, put it into the Raspberry, but when I connect to power supply, nothing appears in the monitor (HDMI connected previously), not even the so called Rainbow screen. Am I missing something?? This is getting so frustrating.
PD. I forgot to add, a red light is visible inside the case when the power supply is connected, so electricity is flowing apparently.