During the normal (usual) mode, the status of GPIO0 and GPIO2 will be high, and grounding GPIO0 sets the chip to programming (bootloader) mode. In short, to flash an ESP-01 module, it should be ...

PC communication is via a FT232RL USB-UART converter over a Mini-USB connector. ... As of now, the dev board only supports the ESP8266-01 module.

In addition to the ESP-7 or 12 module (which plugs in via a header, should you need to swap it out), the board features a CH330N USB to UART chip and HT7233 voltage regulator.