Well firstly, it's not 'my' circuit, it's basically taken from the datasheet.
But it's a 'charge pump', think of the capacitors as buckets of electricity, been carried up and emptied into a larger bucket.
For a simple 'example' imagine another capacitor C6 in parallel with C5, let it charge up and then remove the capacitor, and reconnect it with it's -ve end to the +ve of C5. C5 will have 5V on it, but C6 will have that 5V plus it's own 5V, making 10V on C6. That's crudely what the chip does.