Cranky correction: That’s not a schematic, it’s a layout. Schematics are usually much better organized to make clear what a circuit is doing. Layouts are a pain to analyze (and figure out if they make any sense or not, as @dud suggests there are many bad circuits on the web.).
With a 100k pot and a 10 nF cap the minimum frequency will be something like 160 Hz. That may be too fast to see the LED blinking. Persistence of vision and all that. If you have a larger cap you could try that for a lower frequency that might be easier to see.
But really, you need to hear what’s going on! In the US anyway (don’t know where you are) it’s yard sale season, finding a dirt cheap powered computer speaker or something like that shouldn’t be hard.