I have a workflow which has 2 review statuses as follows:

If the initial assignee clicks the "TL Review" button, the issue should be transitioned to the Team Leader. And if the Team Leader click the "PL Review" button, the issue should be transitioned to the Project Leader/Reporter.
However, the team leader is variable by project, thus I add a role named as "Team Leader" and add the only one team leader in it while creating the project.
But I don't know how to make the issue automatically be assigned to the Team Leader after the initial assignee click the "TL Review" button.
Is there any free solution to achieve the workflow?