Start sequence with momentary switch & prevent pin from reading for set time

Hi all,

I can’t seem to bust through this small hurdle.

I want to use a momentary button to start a sequence of events run off a timer and millis. I have it working with a tactile button but when I switch out the button for a momentary one everything stops working when I let go of the button. I have every start with a if statement that goes

if  (digitalRead(buttonPin)==HIGH)
{ 
do stuff
then other stuff when the timer= certain millis value
}

What am I missing. It seems simple but I am so hung up on it.

ALSO
This project runs through a series of actions when a button is pushed. I also want to prevent the button from reading if it is pushed while the events are going on and allow it to be sensed when the sequence is done/certain millis is reached. Can this be done with a while loop? If not than what?

Thanks for any help!

boolean running = false;

...

if  (digitalRead(buttonPin))
   running = true;

if (running)
{ 
do stuff
then other stuff when the timer= certain millis value
when the last thing is done, set "running = false;" to stop until the next button press.
}

I am not able to get this to work for the reading the initial momentary button push. In this I believe this will work well for getting it to prevent the button hitting until the end though.

snippet of my code:

boolean running = false;

void loop(){

if  (digitalRead(buttonPin))
   running = true;


if(running){
  start=millis();   //start is my timer 
  delay(200); 
}

I have an long called elapsed for elapsed time and I am saying

if(elapsed>1000){ 
led on 
}