"No, do not go!"

[peter2108]

This is to a group of people? No, non vai to ask an individual not to go?

[mukkapazza]

The imperative works in two different ways. "Non andare" is for a single person, your son, your cousin, your friend, but it shows up on public signs as well. "Non andate" is for addressing a group, just like you said.

[peter2108]

But I was wrong about No, non vai which should have been No, non andare (infinitive for negative imperative as you say) but Si, vai is correct. But now what about Vada a bordo which, famously, means "Get back on board". But how?