How can I assign the role of "Talent Pools Manager" to an existing talent pool?

Only Recruitment Managers can assign the role of "Talent Pools Manager". Go to "Recruitment" in the left side bar > "Talent Pools" > select the talent pool and click on the three dots next to the talent pool > click on "Manage" > in the "Talent Pools Manager" section type the name of the employee or select them from the dropdown list and click on the "+". Note that you can assign the "Talent Pools Manager" role when creating a talent pool.