raspberry+hifiberry digi+monitor touch problem

hello everyone. I just put in operation raspberry conn hifiberry digi and official touch monitor. powered in the machine with a power supply switch from 2.5 amps. I have the yellow lightning on the top so probably the power supply is not enough. fine.with the monitor from problems. what kind of power supply do you recommend?
sorry for bad traslate…

Hello everyone. I changed the power supply, now the yellow lightning and disappeared .ok.
but I do not understand why without the monitor I kept the raspberry under key and never gave any error.ora just turn the key turns on but no longer recognizes the key. if I take the key and put it in the pc tells me error reset.I understood that you have to turn off volumio correctly. but without a monitor it did not happen. Please help me

sorry for the bad translation. I think I understand the problem. Second me and a power problem. The raspberry needs 5 volts. The hifiberry digi card is not enough. How do I separate the two cards since they are connected via the gpio? in the meantime I try to re-install volumio in case it is corrupt. In the hope of receiving assistance.
thank you