The circuit is split in two parts: the first part implements the switching logic:
whereas the second part implements the actual power-switch for the Pi:
Note that this graphic documents two possible implementation variants. The second part connects to first part on the right side (labeled "zu S2").
We also provide a layout for the pcb (seen from above):
Wall-power supply is top-left, power to the Pi is top right. The pins on the right side go to the RTC and the Pi. The following image shows the circuit on the left, the RTC in the middle and the Pi on the right:
Please also have a look at additional files in the doc-directory: you will find a parts-list in oocalc-format (German suppliers, but it should get you going).