Gallery Slideshow

I am using NextGen Gallery plugin in my wordpress website. And I want to show a option like gallery, which can show all the images in my database. But I am not able to show gallery in my gallery section, it is coming in sidebar only.
Basically I want a gallery button in my navigation bar so that if somebody click n that button it will show all pictures in my gallery section which I have created in nextGen’s settings.

Thank you