You only run the PluginManager.
Basically, what jBridge does is: it creates a new plugin dll, which loads another plugin dll.
By running the jbridger tool, you create these new plugin dlls.
You don't have to run jbridger anymore, because the plugin manager creates the new dlls for you.
Plus, it keeps your plugins and your various dll files (original plugin, jBridge dll, automap dll etc.) organised. It creates a folder for your host to scan and puts the relevant dlls in this folder or in subfolders, as you categorizes your plugins.