Thank you for your answer. About the point 3, as far as I know, the Raspberry works well with the 1A power supply that we use for charging our mobile phones. The 2A power supply is needed if you need to connect a lot of external devices (for example, an hard disk). Is this the situation?
Yes otherwise it may not have enough power to run. Unless of course you invest in a powered USB hub. Typically you’ll know you aren’t getting enough power when either peripheral devices don’t work or a rainbow square shows up in the top right corner of the screen.