Is it possible to auto select all rows in a model

I’m trying to achieve the following result but having a hard time.

Currently, I have the following models:

1. Opportunity Model,
2. Project Model,
3. Project Deliverable Model and
4. Opportunity Project Deliverable Model.

When I create an Opportunity and add a project from the Project Model. I want all the Project Deliverable based on the project from the Project Deliverable Model to be added to the Opportunity Project Deliverable Model. All the models are Salesforce Object. My question is it possible to automatically add all the rows from one model to another. I tried using action trigger and create new row(s). But When I do that, I'm able to add only one row. Any suggestion will be helpful.