Millis after digital read

How all i do plc ladder programming but i want to do an ats project but i cannot use delay because it pause the program it can make confict when Ceb came back.Here part of my code can anyone help me how to use millis in it?

const int Ceb = 1;
const int Gen = 2;
const int Genon = 3;
const int Genss = 8;
const int Gensup = 9;
const int Cebsup = 10;

int CebState = LOW;
void setup() {
// put your setup code here, to run once:

pinMode(Ceb, INPUT);
pinMode(Gen , INPUT);
pinMode(Genon , INPUT);
pinMode(Genss , OUTPUT);
pinMode(Gensup , OUTPUT);
pinMode(Cebsup , OUTPUT);}
void loop()
{ CebState = digitalRead(Ceb);

if (CebState == LOW) {
digitalWrite(Genss , HIGH);
(MILLIS) how can i use millis here 5 seconds delay
} else {
digitalWrite(Genss , LOW);

}
}

https://forum.arduino.cc/index.php?topic=503368.0

The demo Several Things at a Time illustrates the use of millis() to manage timing without blocking. It may help with understanding the technique.

Have a look at Using millis() for timing. A beginners guide if you need more explanation.

...R

Thanks all for great help