I'm trying to do something that I would assume is very basic, but I'm struggling with it. I have two entities, Contact and Activity. There is a one-to-many relatonship established (a Contact can have one or many Activities.)

I have a home screen that lists my Contacts. When I create or edit a Contact, and I have a nested table records that lists all the related Activities. There is a button to create a new Activity. This launches a pop-up where I can then create a new Activity. The issue is that I've created a combobox to select the Contact, however, I do not want this. Since I am in the context of a Contact whenever I create or edit an Activity, it should automatically create the Activity related to the Contact, without the user having to select the Contact from a combobox. How can I achieve this?

In the Save action, take the id of the current contact and save it in the other record
Can you provide some more details? I have a "CreateOrUpdateActivity" action in my "Save" action, but how do I retrieve the ID of the current contact?

If you have a List, for example, to show contacts, and a user needs to click on one to show the Activities in the list below. You need to make reference to the id of the chosen Contacts record (e.g. ContactsList.Current.Contacts.Id) or, if the Activites are in a web block, you need to pass it as a parameter. When you are creating the Activity record, you need to assign the value of the Contacts Id to the appropriate field in your Activity record before you write it (i.e. the record you use in CreateOrUpdateActivity).
Hi Bailey,

I think this online training video will help you. It is for the many-to-many relationship but since what you are doing is list the n relations of the 1 contact on the contact page I think you can map the concepts on the video to your example.