How do you add ASK as search engine?

Is this to your browser or simply to use ?
Please clarify your question.

Um, if you have chrome just star item on the side and have item appear as a bookmark. The same would apply to internet explorer. Other than that you can go on ask.com and see how to add to toolbar.

Either add the ask.com toolbar to your browser, or go to tools, then internet options, then change your homepage to http://www.ask.com and hit apply. After that, each time you open a browser window, it will go straight to ask.com, but I would say the toolbar is the most quick and easiest way to accomplish your goal.