First, let me explain the network or ministry feature: this is for you to track a group of people or a certain number of smallgroups. By adding a network you can see statistics for this network. For example: You need to track the youth group and see how is it growing or need to track the all the kids small groups.
This is how you create them:
Go to Networks in the left side menu
Click on the network button and fill out the information
If the leader that you want is not showing is because you have to add them. See article Adding a leader.