1. To Change the wallpaper right click the Windows Icon in the far bottom left.
2. Go to Settings.
3. When settings has opened, select the Personalisation tab.
4. Once in the personalisation tab, go to the Background tab and select between Picture, Solid colour and Slideshow.
5. When you select picture, you can select a computer default wallpaper or you can press Browse where you can select a photo off your computer to have as a wallpaper.
6. Once you have selected a picture it will change there is no apply button, it should just change once you have selected a different one.