Theme WP-Creative

Hi all,
I really like this theme but having problems trying to understand certain sections such as the Slideshow.

When adding the custom field… I’m expereincing Posts disappearing and in some cases its as if the first thumbnail image is overlapping another (frustrating… wasting hours going around in circles).

Can I ask if pages can be linked to the slideshow category? At present it seems that only Posts are linked#

If someone could take a look at the domain as advise it would be appreciated.

https://www.interactive-advertising.co.uk/www/

I would really appreciate some guidance and/or a call to discuss further.

Thanks in advance
David
[Telephone number removed]