Go to the interview tomorrow, and if nothing happens, go to work the next day. It's a grass-roots post. But I have an appointment with my brother to travel for two days this Friday.

This is not a question of grass-roots posts, but a question of your attitude. On such a first day, you must go to work. I think a person's attitude is very important, especially the newly graduated college students. The room can be returned after it is booked, and it won't cost a few dollars. HR lets you go to work, which means you are recognized. It's not good to just go to work.