How to change the height of a parallax slider?

Hi Support,

I’m currently having issues with the height of my parallax image. It’s too small!
I’ve had a good search and can’t seem to find an answer so here I am!

I’m currently working on a project and I’m yet to move over to paid hosting.

So the question, How can I make the height of my image bigger? I’ve tried height: 80% but nothing has changed.

The link to the website is…

http://nkfproperties.getfreehosting.co.uk/

also, I’ve followed this tutorial (the updated version, not the parallax plugin)

How to add parallax scrolling to a Page Builder row.

Thanks in advance!