In my experience the "folder" option is to import a list of .VOB files to be combined into one output file.
I batch render by queueing the jobs up as quickly a i'm able and letting them all run unattended. It's pretty easy and takes only a couple seconds each if they all use the same template.
Dunno that there's much to tut. You know how to start handbrake rendering, right? Just do the same thing again for the next file. There's no need to wait for the first one to finish. I can queue up 10 in a minute and then let them rip.
The "trick" is to find the Queue All or Add All button that is just below the Add to Queue button. All I did was selecting the folder with all my source files, named the first file and path and then add all to queue. HB will add all the files in the folder to the queue and name them automatically provided you have set a path in the options and enabled auto naming. That should do it.
Set the output file path, auto naming and auto file extension.
Under Source, use "Open Folder". One of the files will be then shown under Destination - File. Under "Add To Queue" is the "Add All" button, that should do it.
Your queue should show all the files in the folder with their destination, press start ad it will run.
HAh! It was under the Select Folder that I was left with a blank directory, until I realized that ALL I had to do was select the folder and NOT an actual FILE for HB to make a selection from. That's where I was misunderstanding. You said : "Under Source, use "Open Folder". One of the files will be then shown under Destination - File." - well, that wasn't the case 'cos I hadn't, couldn't see any files to select! What you and HB were telling me, in reality, was to go up or back a directory. Sure, once I'd done it "once" I see what it was about. Nasty or rather misleading workflow indicators?
I sometimes used the batchrendering option of Handbrake, I remember that it is also important to choose your rendering template BEFORE importing/adding the "Folder" to the Queue.