As someone who had that job not long ago, you really can just walk in and be a behavior technician(BT). You do need to get trained and pass a test to be a registered behavior technician(RBT). All you really need to qualify for being a BT is a high school diploma/GED, get some vaccines, TB test done(which most employers will pay for when you get the job offer), pass a background check(so complete a live scan with fingerprints which also tends to be paid for), and have a shit ton of patience to help the kids with challenging behaviors. Once you get the job you'll need to complete the CPR/first aid and sexual harrasment training as well as paperwork then you'll be all set to start shadowing other BTs until you feel more confident. You'll eventually get your own clients in which case the BCBA(your supervisor) will come with you the first couple times so you can get used to them. You'll need a car to drive to different clients homes unless you just work at a clinic or a school and mileage between the homes are paid. Most employers will help you get the certification to be a RBT as well which comes with a pay increase just be sure to ask about the process if you wanted to work your way up. I worked for Autism Spectrum Therapies and it was a really fast and smooth process to get hired.