Please help me any english expert out there. Forgot to buy ticket for my boss?

Boy, all you can do is apologize sincerely. All over this email, your boss is telling you to get reservations for steve. Next time, print out & cross off or check off each task as you do them...you would have seen a huge chunk of stuff you did not do on this one (steve ticket....steve accommodation...check date with steve......). You are correct, this is a pretty big boo boo. You will need to make a plan to formulate a system so you do not do this again--and tell your boss the changes you have made to protect from future mistakes like this again.