If your interest aligns with this:
The NanoVNA is a nice piece of equipment for not a lot of money. I have an H model.
It does have a steep learning curve which would be true of any VNA.
Build yourself a wire antenna. Make it cheap, use speaker wire from the hardware store. Download the free copy of Eznec and model the antenna in it. Use the Nano to tune it and compare it to the model.
When your done, you'd have a good fundamental understanding of antennas, a beginning knowledge of antenna analysis, and you'll know the vna well enough to tackle other vna work like evaluating baluns and circuit impedences.
There's plenty of resources on the internet to help you figure it out.