Need Assistance Using Fusion to Assign Multiple Users to All Appropriate Tasks (by Role) on Newly Created Project

I have been working on a scenario that looks for specific new requests/issues and then grabs all necessary data, to include user data for three different roles to be assigned to the converted issue/project. After converting the issue to a newly created project I need to then assign each user to all of the tasks that are assigned to their role. I have tried multiple things from searching for all child tasks on the project, then using the assignments list as a filter and misc action to try to assign multiple users and nothing is working. Any assistance or guidance would be super helpful!