I know you think you've got an answer, but let's give it another try.
First of all, you should get familiar with the double-slit experiment.
Don't just sort of memorize it, but puzzle over it until you can see the ramifications.
What it's saying is that there is something that acts like a probability wave.
Normal waves, like in water, work by interfering, that is, by reinforcing and/or canceling each other.
We call the height of a wave its amplitude, which can be positive or negative at any
place and point in time.
When two amplitudes hit each other and have the same sign, they add together to make a big wave.
When they hit each other and have opposite sign, they subtract and make a small wave, or no wave at all (at that place and time).
You knew all that.
A wave also has energy, which is proportional to amplitude squared, and it is always positive, right?
If you square a positive number, the result is positive.
If you square a negative number, the result is positive.
That way, whether a wave at a particular place is "high", or "low", its energy is always positive.
OK, now here's the leap into quantum-land:
There is a kind of wave whose energy at a place and time is equal to the probability that a particle exists at that place and time. That is the particle's wave function.
Back to the double-slit.
A single particle is shot from the gun.
It continually exists at a place and time, which is to say its wave function has a big lump of energy there.
But, the wave spreads out.
Part of it goes through slit A, and part through slit B, and part gets lost.
On the other side, the remaining two components of the wave travel forward and interfere, as waves do.
So finally, at the screen, there are places where the waves cancel out, so there's no energy there, so there's no probability there, so there's no particle there.
There are other places where the waves reinforce, so there's plenty energy there, so there's plenty probability there, so the particle is likely to be found there.
That's the key idea.
You have waves of a "substance" where the energy in the wave is the same as the probability of something.
That should make you think, because it means we don't actually know what's so.
We only know possibilities, and those possibilities conspire among themselves.