He already told you the answer.
An example using your code:
int trigger = 0; //globally define the trigger
void loop()
{
valF = analogRead(forcePin); // read value of force sensor
valS = digitalRead(switchPin); // read value of switch
if (valF>=thresHold && trigger == 0) { // waits for force sensor to equal or pass pressure threshold
//and makes sure the button hasn't been pressed before
trigger = 1; //signal that button has been pressed before to prevent re-triggering
delay(1000);
digitalWrite(RedPin, LOW); // turns on red LED
delay(1000); // waits one seconds
digitalWrite(RedPin, HIGH); // turns on red LED
delay(500); // waits half second
}