Deploy 12c Management Agent

Here explain how to add target hosts to enterprise manager

Login to Enterprise Manager via Sysman login
Go to Setup->Add Target->Add Targets Manually

 Select Add Host Targets and Click Add Host Button

Click on Add Button and Add the target host name which need to deploy agent and Click on Next Button

Provide Installation Base Directory and Instance directory on target host

Review the Host Information and click on Deploy Agent button to begin the installation

Now Management Agent will deploy on target host

Ignore the Privileges warning and click on Continue->Continue, All Host

Run the root.sh to complete the Agent deployment

Go to Setup->Add Target->Add Targets Manually and select 'Add Target Declaratively by Specifying Target Monitoring Properties'
Select 'Database Instance' to Target Type and specific hostname for Monitoring Agent and click on 'Add Manually' Button

Provide Database Details of Agent and Test the connection

Agent configuration completed and now can monitor newly added DB through EM