As explained in the properties table, when you select the Custom option from the Distribution drop-down list, you are connecting to a Hadoop
            distribution different from any of the Hadoop distributions provided on that Distribution list in Talend Studio. 
      After selecting this Custom option, click the 
            
            
            
            button to display the Import custom
                definition dialog box and proceed as follows:
    
      - 
            Depending on your situation, select Import from existing
                version or Import from zip to
                configure the custom Hadoop distribution to be connected to.
            
               - 
                  
If you have the zip file of the custom Hadoop distribution you need to
                        connect to, select Import from zip.
                        
                        Talend
                      community provides this kind of zip
                        files that you can download from http://www.talendforge.org/index.php.
                
               - 
                  
Otherwise, select Import from existing
                        version to import an officially supported Hadoop
                        distribution as base so as to customize it by following the wizard.
                    
                
            
            
            Note that the check boxes in the wizard allow you to select the Hadoop
                element(s) you need to import. All the check boxes are not always displayed in
                your wizard depending on the context in which you are creating the connection.
                For example, if you are creating this connection for a Hive component, then only
                the Hive check box appears.
          
- 
            Whether you have selected Import from existing
                version or Import from zip,
                verify that each check box next to the Hadoop element you need to import has
                been selected..
         
 
- 
            Click OK and then in the pop-up warning, click Yes to accept overwriting any custom setup of jar
                files previously implemented.
            
Once done, the Custom Hadoop version
                definition dialog box becomes active.
            
            This dialog box lists the Hadoop elements and their jar files you are
                importing.
          
- 
            If you have selected Import from zip, click
                OK to validate the imported
                configuration.
            
If you have selected Import from existing version as base, you should
                    still need to add more jar files to customize that version. Then from the tab of
                    the Hadoop element you need to customize, for example, the HDFS/HCatalog tab, click the
                        [+] button to open the
                        Select libraries dialog
                    box.
          
- 
            Select the External libraries option to open
                its view.
         
 
- 
            Browse to and select any jar file you need to import.
         
 
- 
            Click OK to validate the changes and to close
                the Select libraries dialog box.
            
Once done, the selected jar file appears on the list in the tab of the Hadoop
                element being configured.
            Note that if you need to share the custom Hadoop setup with another
                        Talend Studio, you can export this custom connection from the Custom Hadoop version definition window using the button.
          
- 
            In the Custom Hadoop version definition
                dialog box, click OK to validate the customized
                configuration. This brings you back to the Distribution list in the Basic
                    settings view of the component.
         
 
      Results
         Now that the configuration of the custom Hadoop version has been set up and you are
        back to the Distribution list, you are able to continue
        to enter other parameters required by the connection.
         If the custom Hadoop version you need to connect to contains YARN and you want to use
        it, select the Use YARN check box next to the Distribution list.
         A video is available in the following link to demonstrate, by taking HDFS
                as example, how to set up the connection to a custom Hadoop cluster, also referred
                to as an unsupported Hadoop distribution: How to add an unsupported Hadoop distribution to Talend
                    Studio.