There's something wrong here.
The handle isn't supposed to point straight up, and surely it shouldn't stick so far out of the tank...
Which shows me that the stick thingy is remaining vertical, which makes the chain way too long and it is now stuck under the little trap door thingy. If the trap door thingy doesn't close, the water keeps running out which makes the ball not rise the way it should. If the ball doesn't rise, more water keeps running into the tank. I moved the round white thingy up to the handle and screwed it back on.
It's possible I have inherited the non-plumbing gene from one of my parental units (who shall remain nameless), which means I will end up making three trips to Grover's.
We'll see if it holds.
The suspense is killing me.