People approach solving jigsaw puzzles in different ways.
One way is to randomly select pieces and see if they fit together. And then repeat, waiting for a chance encounter to happen. Over time, you'll find more pieces that connect through the simple process of trial and error.
Another way is to take a look at the picture on the box that the puzzle came in and find the pieces of the puzzle that might resemble parts of those images. You might have better luck doing it that way. There might be a distinguishing feature on the image that you can use to help guide you.
I like to find the four corners first and then build the perimeter of the puzzle. Once that is complete, I'll work from the outside in.
Regardless of how you like to do puzzles, it helps immensely to have an organizing principle which will enable you to sort the pieces a certain way and then you can start figuring out how to solve it. There is no right or wrong way to do it. One method might be more time consuming than others, but you have to find what works for you.
How you structure your approach can have a dramatic effect on your outcome, particularly when coupled with a steady effort over time. Being specific about what you intend to do will help clarify the effort that you need to make on a project.