This has to be done by an App manager.
To assign influencers:
- Click on your avatar at the upper right hand corner and go to Manage > Manage application > Setup > Privileges. Then scroll down until you see Influencers.
- Type in the name of the person you wish to assign as influencer. When you start to type, you'll see a list of people to choose from. Select the name(s) and click Save.
This person's posts will now be given more prominence in the Feed and latest/popular tiles.