I found this for DC-DC buck converter , Is it good ? If it isn't can you advice me . Here what I found https://www.amazon.com.tr/Protection-ayarlanabilir-Dönüştürücü-Step-down-Function/dp/B0768D8L7D
"I don't know what J1 and J2 are for so you're on your own in checking if they make sense like this." J1 Is ,When I need UART , I will use this.(I am thinking add rfid).
J2 and J3 is (j3 is on first photo below hx711) These are TB6600 pin cable.
Tx-Rx connection good . I am using Esp TX to Arduino's RX and Esp's RX to Arduino's TX. (pin 0 TX, pin 1 Rx on this microcontroller)
I will make pin 9 and 8 connection.