WIFi D1 mini PRO is an integrated ESP8266 based WiFi enabled microprocessor unit + 32Mb flash memory.
There are an CERAMIC WiFI antenna and socket for connecting external antenna embedded on board.
For communication with PC (USB-TTL), it uses USB driver CP2104 (needs install a driver)
WIFi D1 mini PRO board uses the Arduino IDE for development.
For power, you can use USB 5V, or any DC power 4-9V to pin 5V (if have any shield for use 5V, better power supply exactly 5V).
For a battery, connect it to pin 3.3V .