Ronaldo may very well be one of the greatest football players on the planet, and it is such a shame that your poster got torn up by jealous kids. Being the only poster of its kind, you decide to suck it up and put it back together, just like a jigsaw.
In Ronaldo Jigsaw you need to use your left mouse button in order to click and drag the jigsaw pieces to where they belong. If you want to speed things up a bit you can always select and drag multiple pieces with the help of CTRL + Left Mouse Click.
There is a time limit which you would do well to keep a watchful eye on, although rest assured that it can be turned off should you desire to simply relax while putting a puzzle together.
There are four different difficulty levels available, ranging from easy to expert, each one increasing the challenge by breaking the puzzle down into more pieces.