International flights- off topic

This is my busiest group so, I’m hoping to get some quick helpful responses. I am cutoff work & have some time to visit family in Mexico, my in-laws who I have never met!! 🤗 The thing is I have never been on a plane & have the slightest idea on finding the best prices flights. If any travelers could help I would truly appreciate it! I would be departing Newark, NJ airport and am looking to fly into Mexico City. It would be me & my 5 yr old son. I prefer a nonstop flight & would like at least 1 carry on, that’s something I was confused about when searching, some allow them others don’t 🤷🏻‍♀️ I am wanting to go for 6-9 days, leaving ASAP but returning by the 18th. Please help ✈️🛫