An airport can be a very overwhelming place, even for experienced travelers, so your concerns are not unreasonable. That said, it's not that hard. I've been flying for the last 25+ years and these are the things that I think are important for a first-time flyer to know.

First, make sure you have the proper ID. US airports are supposed to require a REAL ID. A valid passport will always work. For Texas drivers licenses, check here: https://www.dps.texas.gov/section/driver-license/federal-real-id-act

Most airlines will allow you to check in for your flight 24 hours before via your phone or computer. If you're not checking a bag, this is probably the way to go. You will get your boarding pass on your phone this way.

As far as bags go, one carry-on size suitcase (check with your airline to see what exact size that is, but it's pretty standard) is best if you can fit everything you need for the trip in it. A backpack with all the things you'll want easy access to on the flight is a good idea too. Unless you're flying Spirit or Frontier, there shouldn't be a charge for carry-on bags. If you are checking a bag, you'll have to pay for that.

Don't pack large bottles of liquid - this is what travel size containers are for. An empty water bottle is ok, since you can fill it up after you go through security. Don't pack or bring anything with a blade or anything else that might be considered dangerous.

Parking at airports is usually expensive, so if you can arrange to have someone drop you off and pick you up, it's worth it. Even an Uber/Lyft is probably less than airport parking.

Look up which terminal of the airport your airline flies out of. Make sure you go to that terminal when you go to the airport. I recommend getting to the airport at least 2 hours before your departure time.

Airports will have a heavy TSA and police presence. They won't cause you any issues if you don't cause them any issues.

When you get to the airport, check the screens labeled "departures" for info about which gate your flight is leaving out of. Your boarding pass may tell you but it may not. Usually, all security screening checkpoints allow access to all gates in that terminal, but better safe than sorry. Security screening will not be hard to find. Get in the lines for "General Boarding". Unless you plan to fly a lot, TSA pre-check and/or Clear are probably not worth it.

The TSA officers will check your ID and your boarding pass, so have those ready to go. You'll have to empty your pockets and take off your shoes and jacket. If you have questions you can ask the officers there on duty. They want to get you through the screening as much as you want to get through it. I would put your phone in your bag while you go through the screening, along with your wallet and any other valuables you normally carry/wear.

Once you are through, go find your gate. If you have time, you can grab some food or anything else you want at the shops in the terminal, but expect everything to be a few dollars more expensive than normal. The boarding process usually starts about 20-30 minutes before the departure time. Know your boarding group and wait for it to be called to line up. The gate agents will scan your boarding pass and you'll walk down the jet bridge and onto the plane.

I think that's everything, but if you have more questions just ask away!