Automatic popup when opening the page

Hello, I'm new here and I use GRAV CMS only recently. I have the following problem.
I want zu open an Infobox / Infomassge like this:
https://demos.crazedbytes.net/shortcode-modal

I can the code copy to my Grav-CMS and it works too, but I would like the night message / info box to appear automatically when the page is opened without a button click. Do any of you know how I have to adapt the code so that it is automatically executed when the page is called? I am grateful for every tip. best regards Andy

Here the orginal Code:

[modal name="example1"] 

Hello, World!

[/modal]

[modal-launch modal="example1"]Launch Modal[/modal-launch]

Hi,
via the plugin if option exists or simulating a click with jquery

Hi, I can't find any options for the "shortcode modal" plug-in except for the demos, that's my problem.
How could such a click with jquery look like?