It offers two ways. The first one is very simple, you only have to choose the photos you want to include and the template you want to use and it will create the collage automatically.
The second one offers you more options and features. You have to choose the pictures and place them, rotate, apply masks, filters and more. Add all the pictures you want and sort them as you want.
Finally you can export the result as jpg, png, bmp or set it as wallpaper in one click.