add custom background to theme bootstrap3 custom-background

Hi

I am trying to learn wordpress and I’ve built my own personal theme on the bootstrap3 framework and added the wordpress navigation successfully etc.. However I am trying to add the functionality of a (custom-background) via the admin panel.

I’ve added the following code into the functions.php file;
add_theme_support( ‘custom-background’ );
However on changing the colour or uploading an image nothing happens to the website it remains white background: https://creative-media.info/Peugeotmaintenance/

Any help and advice would be greatfully appreciated, I’ve googling the issue and not found any info regarding to this issue? I’ve even changed the body background tag in my CSS to a dark red then uploaded this worked. However I want to create the ‘custom-background’ effect

cheers

Paul