ESP-12-F development card...

Hi,
I got from Amazon a HW-546 ESP8266 Development Card Cloud Witty ESP-12F (see picture).

But without details about it, I can’t use this module as is…

So I try to find it’s data sheet on the net, but unsuccessfully (I just found the one related to ESP8266 itself…).

Presently, I would connect it to an arduino nano for programming with the IDE on a PC with W10.
This module has 2 µUSB, one on top and one on bottom PCB.

First, as I know that ESP8266 needs 3.3 V (and not 5V), I would know if this module as a DC-DC step down (5 V->3.3V).

What is the use of the upper and lower micro usb?
Is the upper one for power and the lower one for programming with IDE arduino using USB on the PC?

NB: I just end a project using 2 ESP8266 (one as a web server for transmitting the state of GPIO0 connected to a switch, and the other as a wiFi client which sends requests to know the changes and drive the LED_BUILTIN cf picture). All is working but now I would experiment the development module.

@westfw: Ok, thanks, this site is well documented! (waiting the reply, I finally found a US web site that describes in details this development module: ESP8266 Witty Cloud ESP-12F WiFi Module - ProtoSupplies but yours has more drawings...)