Carefully put solar module on some soft underground so the front does not scratch. Then cut the long wire to around 50cm (see backside image as reference). Everything will be put in the back of the panel and there is plenty of room.

Solder and connect the components around the ESP32 (see schematic for reference). The GATE of the IRF3707Z should be connected to PIN17, the SOURCE should be connected to GND and the DRAIN is connected to Vin- of the DC-DC Step Up converter.

Solder and connect the 10kOhm resistor between GND and PIN36, the LDR should connect PIN36 with 3.3V (between GND and RST).

Cut the USB micro cable in the middle. Separate the V+ and V- lines and prepare them for soldering (cf. https://en.wikipedia.org/wiki/USB_(Physical)#Connector_types). Since the datalines are not used, also some "charge only" cable can be used.

Connect the USB Micro-B plug part of the cable with the Vout+ and Vout- ports of the XL6009 DC converter.

Connect 18V to the input of the converter and measure the output of the converter with a voltage meter. Now adjust the output via the potentiometer to be 5V.

Connect the V+ and V- lines from the solar panel with the Vin+ and Vin- ports of the XL6009 DC.

Connect the LED V+ and V- cables to the DC DC Step Up converter ports marked with "OUT". Take the remaining part of the USB cable and connect the V+ line with the Vin+ of the DC DC Step Up converter. Connect the V- line with the GND of the ESP32.

Plug in the Micro USB plug from the XL6009 DC converter to the input (charging) port of the battery pack. Plug the LED USB cable and the ESP32 USB cable into the output ports of the battery pack.

Place the LDR at an intersection of space between actual panels on the front so it can "see through" from the back.