user58425: I need a simple code to turn on 12 outputs one after another 2 seconds apart. A pushbutton will initiate this and the outputs will stay on for 3 minutes at which time all outputs will turn off awaiting the pushbutton input
So far:
Void setup 
pinMode (10,output);
PinMode (11,output);
PinMode (12,output);

Void loop
delay(100);
digitalWrite (10,HIGH);
delay (2000);
digitalWrite(11,HIGH);
delay(2000)
digitalWrite(12,HIGH);

delay(180000);
digitalWrite (11,LOW);
digitalWrite (12,LOW);
digitalWrite (10,LOW);
exit(0);

Push remote reset button to restart.
Only tried 3 outputs for now and haven’t tried “Crossroads” code yet but I will.

user2967: Don't use Delay. CrossRoads provided a decent starting point for your code, but his code is based on delay(), which is a dead end.
Instead of delay, use a bool running to track whether you're relay sequence is running or not. Also have an unsigned long startTime, and an array of bools to track if each relay is on or off.
If !running, check the button. If the button is pressed, set running to true, and set startTime to millis().
Then, use millis() to figure out where you are in the sequence. Calculate (millis()-startTime)/1000/num_relays. Let's call it relayIndex.
When relayIndex is less than num_relays - 1, check the bool for that relay, and if it's off, set it on and turn on that relay. When relayIndex reaches num_relays-1, you're done turning on relays. Now it's time to wait for 3 minutes to go by. After 3 minutes, turn off all the relays and relay bools, and set running=false. Have the reset button do the same thing.
EDIT
Also note that controlling relays from an Arduino (or from other solid state devices for that matter) requires special hardware and precautions. You should probably use a "digital" relay (something like this, or better yet this 6 channel relay) that isolates the Arduino control line from the high current needed to drive the relay.
Failing that, you should build a control circuit from a MOSFET transistor and a "flyback diode". Without flyback diodes, the inductive coils on your relays emit "back EMF" which will likely fry your transistors (and possibly the Arduino)

58425: <p>I need a simple code to turn on 12 outputs one after another 2 seconds apart. A pushbutton will initiate this and the outputs will stay on for 3 minutes at which time all outputs will turn off awaiting the pushbutton input</p>

<p>So far:</p>

<pre><code>Void setup 
pinMode (10,output);
PinMode (11,output);
PinMode (12,output);

Void loop
delay(100);
digitalWrite (10,HIGH);
delay (2000);
digitalWrite(11,HIGH);
delay(2000)
digitalWrite(12,HIGH);

delay(180000);
digitalWrite (11,LOW);
digitalWrite (12,LOW);
digitalWrite (10,LOW);
exit(0);
</code></pre>

<p>Push remote reset button to restart.</p>

<p>Only tried 3 outputs for now and haven’t tried “Crossroads” code yet but I will.</p>
 2967: <p>Don't use Delay. CrossRoads provided a decent starting point for your code, but his code is based on <code>delay()</code>, which is a dead end.</p>
<p>Instead of delay, use a bool <code>running</code> to track whether you're relay sequence is running or not. Also have an <code>unsigned long</code> <code>startTime</code>, and an array of bools to track if each relay is on or off.</p>
<p>If !running, check the button. If the button is pressed, set running to true, and set startTime to <code>millis()</code>.</p>
<p>Then, use millis() to figure out where you are in the sequence. Calculate <code>(millis()-startTime)/1000/num_relays</code>. Let's call it <code>relayIndex</code>.</p>
<p>When <code>relayIndex</code> is less than <code>num_relays - 1</code>, check the bool for that relay, and if it's off, set it on and turn on that relay. When <code>relayIndex</code> reaches <code>num_relays-1</code>, you're done turning on relays. Now it's time to wait for 3 minutes to go by. After 3 minutes, turn off all the relays and relay bools, and set <code>running=false</code>. Have the reset button do the same thing.</p>
<h2>EDIT</h2>
<p>Also note that controlling relays from an Arduino (or from other solid state devices for that matter) requires special hardware and precautions. You should probably use a &quot;digital&quot; relay (something like <a href="https://rads.stackoverflow.com/amzn/click/com/B00VRUAHLE" rel="nofollow noreferrer" rel="nofollow noreferrer">this</a>, or better yet <a href="https://rads.stackoverflow.com/amzn/click/com/B07HWHJTBC" rel="nofollow noreferrer" rel="nofollow noreferrer"><strong>this</strong></a> 6 channel relay) that isolates the Arduino control line from the high current needed to drive the relay.</p>
<p>Failing that, you should build a control circuit from a MOSFET transistor and a &quot;flyback diode&quot;. Without flyback diodes, the inductive coils on your relays emit &quot;<a href="https://en.wikipedia.org/wiki/Counter-electromotive_force" rel="nofollow noreferrer"><strong>back EMF</strong></a>&quot; which will likely fry your transistors (and possibly the Arduino)</p>
