Add Direct Reports as User Attribute to FIM portal

I have created a user binded Direct reports attribute I want to display in the FIM portal in the user profile.

I am having an issue with populating this attribute. I need assistance on how to complete this... I am a novice on sets and workflows and MPR. I know from research it is a combination of the 3, I just am not sure how to actually populate it.

any help is appreciated.

Thanks

Russell Lema