I don't think he even knows what he is going to do. Plus, he can only order it done. He doesn't actually do anything himself. Even if he orders it there is a chance that it won't happen. But he's crazy. He may have a death wish.
Only God knows what is going to happen. But frankly, nothing would surprise me. It would not surprise me if (seeing a missile being moved into place, or several missiles) Trump put some missiles on point to take them out preemptively (Is that a word?). Any kind of 'Before The Fact' attack will probably bring down the ire of the world.
But I'm not sure Trump cares. He seems to think that he should do what is in the best interest of America, regardless of what anyone thinks.
Personally, I prefer the active, rather than the passive approach. But I know that is not a universal feeling by any means.
So, if you're not God, then you'll just have to sit back and wait to see what happens.
By the way, I love putting my 2 cents in. But I feel guilty that I'm overcharging for it!