I started off by making a mock-up again on Powerpoint. After finishing this mock-up, I decided that I wanted to make the final image a square as the photos matched up at the edges.

I then selected the images I used and cropped them in Lightroom.

After this, I opened them in Photoshop and formed my joiner.

I then added a Gaussian Blur to some of the image fragments.

After this, I altered the brightness, contrast and exposure of each of the images to get my final result.

This is my final joiner: