There is nothing needed to configure the first time you use Meta Slideshow, just start the app and the slideshow will start playing. It can not be easier.
If you wish you can set some preferences in the Settings app. Open the Settings app, scroll and open the "Meta Slideshow" setting. In the Meta Slideshow preferences you can specify the time each photo is shown. You can also indicate whether you'd like to include the EXIF metadata added to the description.
Double tap to pause the slideshow
With a double tap on the photo you can pause the slideshow, so you can watch this photo in detail. Double tap again, if you want continue the slideshow.