@OCogan I have a configuration for capturing/triggering based on content being downloaded on the website.
Form to capture information - takes to Thank You page.
On the Thank You page, have a CTA button that takes the visitor to the download (which would be hosted in the Marketing > Files). You can then use the CTA click as a trigger, to create lists, etc.
If you have access to it, the Behaviour Events offer a bit more freedom but require a bit more technical knowledge to implement.
Hope that helps :).