Any ESP32 Dev board.
The software.
How to install it.
Wiring is easy.
ESP32 pin simpleRTK2B pin
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GND to GND
RX0 to RX2
IOREF to 3v3_OUT (both on RTK2B)
The IOREF connection ensures that the RTK2B board communicates with the ESP32 at 3.3 volts, which the ESP needs.