This circuit is a rectangular oscillator, that generates a square wave form, the circuit uses NAND logic gates, using CD4011 (contain 4 nand gates), the generated signal can be used as an audio alarm (by connecting a speaker directly to the output), or amplified and used as an inverter…
The enable input should be (+V) so that the circuit oscillates, if it’s low, the output will remain at High (+V), If you do not need a controlled input, you can connect the two inputs of the two gates together and remove the connection between the first and the second gate. (like the picture)
This may simplify the wiring.
Caution: the common point of the resistors and the capacitor is not grounded.