First step with 2 led (SOLVED)

Hi I am beginner and I need your help pls
I try second project with 2 led

there is code

void setup() {
// put your setup code here, to run once:
pinMode(10,OUTPUT);

pinMode(12,OUTPUT);
}

void loop() {
// put your main code here, to run repeatedly:
digitalWrite(12,LOW);

digitalWrite(10,HIGH);

delay(2000);

digitalWrite(10,LOW);

digitalWrite(12,HIGH);

delay(2000);

}

BUT i have power on pin 10 and 12 at same time.
Anybody have ide why?

i use Robotdyn nano V3

Ok I have it… i not upload program to arduino.
I must switch to old bootloader

Thanks for taking the time to post an update with your solution novka. I'm glad to hear you got it working. Enjoy!