Is there a simple way to add an little automatic pop up that comes up after the page is loaded?
Well you could make a form in web form builder, that pops up after a given time that's pretty simple,, but..... there could be complications
What do you want the pop up for"
where do you want the popup to appear?
do you want the popup to stop the user from navigating elsewhere until they have completed an action that is required in the popup?
If a user has completed the popup requirement and navigates away, but then returns to the page with the popup for a reason, do you want the popup to appear again or for the popup to only show once per session for the user (this could be annoying for the user if they have to complete whatever the popup requires then to do.
finally if a visitor has popups blocked in their browser settings, a simple popup won't appear anyway.
all this makes for a complicated popup possibly with java scrips
so it all boils down to what you want the popup for and to do