How do I do a Kamehameha Wave?
meditate, cultivate Chi, defeat any bullshit occultist you encounter for xp
If you're used to manipulating the elements you could probably work with fire.
Then basically evoke fire and focus on anything you want to fry.
listen to how Master Roshi does it and do what Goku did to do that too.
It's not worth the loosh. You'd die before you even blow up a boulder.
In the manga it's literally said to equire 50 years of training for a normal human. Unless you're a sayajin, don't bother.
to be fair though, if you have enough energy to do a good enough kamehameha, you're more than likely gonna live far older than the average human.