SmallS3 features:

1. The new more integrated ESP32-S3-FH4R2 with internal 4 MB flash and internal 2 MB PSRAM.

2. 32-bit 240 MHz Dual Core.

3. 2.4 GHz Wi-Fi & IEEE 802.11b/g/n, Bluetooth 5, BLE+Mesh.

4. 3.3V, 700mA LDO.

5. The reversing current blocking diode D2 is rated at 1A with very low leakage current.

6. 17 GPIOs.

7. Standard WS2812B RGB. The RGB is turned off when it's not in use. It will extend battery life.

8. 5V power LED indicator and 5V presence detection.

9. User LED.

10. Whip ANT for Wi-Fi communication.

11. Larger RESET pushbutton does not hurt your finger.

12. Breadboard friendly, the battery connector is placed on the top layer.

13. Includes a set of low profile male and female headers and a 2-pin JST LiPo battery connector.

14. Size: 1.25" X 0.511" or 31.75mm X 12.98mm.

15. Pin spacing: X--0.1", Y--0.4".

Unique features on the SmallS3 board

1. A digital switch is added to turn off the battery level test circuit after the test is done. It will reduce deep sleep current significantly.

2. With a Low Pass Filter, the battery charge status LED does not flicker when a battery is not connected.

3. Long Reset Press (LRP) to enter bootloader mode, it's simple and easy to use, press the reset button until a red LED is lit
to enter bootloader mode. No need to press 2 buttons at the same time. Once you use it, you may like it.

4. Pin-out is designed for connecting TFT and OLED displays without wiring on a breadboard, leaving more space for your circuits.

SmallS3 assembly Instructions are similar to the SmallPICO assembly instructions.

The SmallS3 board is pre-loaded with a test sketch and it will blink all output pins including the user LED at GPIO36.
Before soldering 2 male headers make sure that the SmallS3 board can blink the GPIO36 LED with your Arduino IDE.
If it can't, troubleshoot the problem first before going further.
If you can't Blink-A-LED before soldering, you won't be able to Blink-A-LED after soldering

The SmallS3 is not shown on the Arduino board list, you can use it as the Feather ESP32 board.
In Arduino IDE click Tools-->Board, then select the "Espressif's "ESP32S3 Dev Module" for using the SmallS3.

SmallS3 pinmap:

Schematic: