Newbies Think They Know Everything
Oh, how cute. A new hire who had been here for only two days is trying to explain how to do your job. You’ve only been working in your office for around 84 months. And seeing as how the OP isn’t fired yet, we can only assume that she’s pretty good at what she does.

To be fair, the new hire might’ve just been explaining what he thinks will make her project run more smoothly. However, with only two working days of experience under his belt, maybe he should just sit back and let the big dogs take care of the messy work.