After installing the zencart, I create a custom template using the instruction of zencart site link http://www.zen-cart.com/content.php?180-how-do-i-create-a-new-custom-template. But when I go to admin-> Tools->Template Selection and update the new created template and press the reset bottom of admin->Tools-> Layout Boxes Controller , I can't work on the new template. how can I know that the new template is enabled and ready to customize.
Actually I wanted to know the procedure to enable the custom template which was solved.So the only fault is my site is that I named the template directory and template name (inside the info file) was case sensitively different.
Sorry, but "I can't work on the new template" isn't really a question.
Your only "question" was "how can I know that the new template is enable and ready to costumise." The answer is: it already is. As per the guide in the FAQ article whose link you quoted, selecting your template from the Admin->Tools->Template Selection, and turning on the desired sideboxes in the Layout Boxes Controller ... are all you need to do to get your template visible and functioning on your site.
If your real question is "how do I customise?", there are many additional FAQ articles explaining the many concepts around the many possible things you might be wanting to customize. You haven't stated any specific thing you want to customize, so we can't really answer your "question" with any specifics in that regard.
At the risk of being told that my "answer" isn't really an answer, I'll advise that the right place to get guided help with customizations you wish to make is by visiting the Zen Cart support forum at www.zen-cart.com/forum.php