I am using zpArdoise and have colorbox enabled on album page.

When I click on a image and colorbox opens, the slideshow starts by default and at the bottom of the window there is a link to STOP SLIDESHOW.

How do default colorbox not to start the slideshow automatically?

If it is using the official slideshow plugin you will have to modify it. Colorbox has a parameter for that. http://www.jacklmoore.com/colorbox/

Look at the slideshow.php of the plugin around lines 580-595 and add slideshowAuto: false, to the JS configuration.

I don't have a slideshow foler in plugins

It is an official plugin and therefore in zp-core/zp-extensions of course.

Go to: /zp-core/zp-extensions/colorbox_js/jquery.colorbox-min.js

Change: slideshowAuto: !0,
To: slideshowAuto: !1,

Colorbox will now display with slideshow off unless started by user.

If you have a problem viewing the JavaScript use JavaScript beautifier to reformat. Makes the code much easier to examine.

http://www.javascriptbeautifier.com/

Many more settings available at: http://www.jacklmoore.com/colorbox/

I also had to change z.slideshowAuto?0 to z.slideshowAuto?1

thanks for the instructions

Actually you should change the definition within /zp-core/zp-extensions/slideshow.php and there within the printSlideshowlink() function which calls and executes the Colorbox slideshow.