indeedio, you coded:
void loop() {
digitalWrite(10, HIGH); //
delay(20); // do this HIGH/LOW set for 5 seconds
digitalWrite(10, LOW); //
delay(20);
digitalWrite(10, HIGH); //
delay(10); // do this HIGH/LOW set for 5 seconds
digitalWrite(10, LOW); //
delay(10);
And of course that means you get one on/off flash at the "20"rate, and one at the "10" rate.
And if you want the same thing multiple times, you use for-loop.
How many loops? If you know the rate (20ms delay = 50/sec) then you do it 125 times (125*(20+20)=5000 ms = 5sec.
That is not a particular good way to do it, but it will suffice with the requirements you give. If your next post says, you need to do something else while it is blinking (monitoring a switch f.ex.) then you realize why PaulS recomended the nodelayblink sketch.