How i do two buttons and when i press them bouth then comes a text where it says hello.

Hi,

I can only do one button and when i press the button it comes a I'm only 12 so my English is badtext where it says hello.
But How i do two buttons and when i press them bouth then comes a text where it says hello. But if i just press one button it not say hello. I use javascript and I'm only 12 so my English is bad
Plz help me if you se this plz help.: