All of the above software is free to use.
If you have no modeling knowledge, look at general beginner tutorials, doesn’t need to be about cars. There are plenty of tutorials on the web for pretty much all levels of knowledge.
Start with small projects with few moving parts, as those are more forgiving of mistakes, and easier to fix when you do make them. JBeam is quite complex with a lot of different components, and it’s easier to start with projects that require less advanced notions like suspension or complex deformation.
Try making some scratch JBeam when learning. While there is nothing wrong with re-using vanilla JBeam, you will gain a much better understanding if you make your own instead of just moving nodes around.
Read our tutorials. They’re there to help beginners like you 😃
Don’t be afraid to ask other modders for help!