1) Connect R1 to 3V3 (on NodeMCU) and R2 to adjacent GND. The other relay analogically. But how do I control if NodeMCU gives 3.3V (to activate the relay) or 0V (to deactivate the relay)? Maybe I don't understand how NodeMCU's 3V3 pins work.
2) First relay: connect R1 to D1 (on NodeMCU) and R2 to ??. Second relay: connect R1 to D7 and R2 to ??. I have read that some GPIOs may be used to provide 3.3V voltage from NodeMCU to another device. But what about closing the circuit? There are some, already mentioned, grounds - GND but which would close mentioned D1 and which would close mentioned D7?
Could you tell me how should I connect NodeMCU and the relays to be able to control them? I would like to provide power to NodeMCU using USB.