To Create a process to automatically add contacts to an event go to
Integrations
Global Processes
Select + Process
Provide a name and select Save
Select the process just created
Select edit mode
Select the Blue + (add query button)
Select Contact and ADD
Add a Wait Block (the Amber + and select ADD)
Set the selector to the desired wait times
select the green + button
Select Entity to "Contact"
Select Action Type to "Add to Event" and select ADD
Select the down arrow in the blue box to open the configuration settings.
Select under Query type 'Is in external CRM' and select the a CRM system you like to get the contacts from.
Select the Events you like the contacts be added to in the action section :
Select 'Save Changes' on the top of the page