Basic help needed embedding in page

This is probably a dumb question, but I’m new to WordPress. So please help me.

I’m hoping to embed one category of posts into a page on my blog: https://www.theemdash.com.

I want to embed my “Em Dash Designs” category into the bottom of the page by the same name.

So I included this shortcode onto my page:
[showlist catid=”” lenght=”” listclass=”” excerpt=”” wrapper=”” wrapperclass=””]

And I filled it out as: [showlist 74=”” 5=”” aptools-list=”” true=”” true=”” aptools-wrapper=””]

But when I did this, the only thing that shows on the page is a gray box.

Any idea what I’m doing wrong? (Probably a lot.)

Thanks!!!

https://www.ads-software.com/extend/plugins/page2cat/