Flashing the ESP-01N module - uploading new firmware

Colleagues the story begins as I have purchased sockets with consumption measurement etc. Overmax company and unfortunately they are on WB2S wifi module which does not allow to upload for example Tasmota. On the web I found a pinout corresponding to the ESP-01N module, but I can not for nothing put it into a flash state to upload new software to it.
The modules are as follows: Link
DataSheet: Link .
According to table 2 pinout mode at flash option assumes as below:
Mode RST TXD0 IO15 IO0 IO2
UARTDownload Mode High High Low Low High
Flash BootMode High High Low High High .
however on the module itself I cannot find IO15 which TXD0.
Do you perhaps know how to get it to flash and upload new firmware to it?

Hello, before connecting the power supply the GPIO pin 0 should be shorted to GND. then ESP should enter flash mode

Thank you - probably the problem was that I was trying to flash the module soldered into the socket and something probably voltage-wise wasn't working. Nevertheless, now esptool recognises the chip as an ESP8285, shows the MAC, clears the flash and writes the data, it takes a while like a normal process but then nothing happens. Tasmota's wifi network doesn't appear, I tried to save my wifi network data with Tasmotizer and it seemingly confirms it with a 52bytes send OK message but still doesn't connect to the wifi - it doesn't get the IP from the router....
Do I need to connect anything else to get the wifi to work?

Further to the story - after flashing when the module is rebooted and plugged in it "cuts out" the 2.4GHz wifi in its range - strange? to me too.
I have a Gosund socket with Tasmota which has been running for some time, the address has from DHCP, I ping that IP but when I plug in the module fresh after flashing the ping to that address dies - how do I explain this?

The MAC of the new module is different from that of the working socket so the router will not assign the same IP to it, the pool is not exhausted either and the lease-ach does not show the new module....
Have you encountered something like this?
I flash two new WT-01N modules but they both behave the same.