Thanks Rui, looking at those link now.
Just a min ago I got this to work: https://docs.kentico.com/pages/viewpage.action?pageId=3309730#Managingon-linemarketingactivities(API)-Loggingcustomactivities
This example creates and inserts a custom activity into Contact Management.
I will try the form submit event next, I see where that will help with another item.