Great! You’ve got your horse off to a good start. By now you should be able to walk away from him at least two meters without him moving his feet at all. If he isn’t quite at this point yet, keep working on him patiently – he’ll get it eventually.
The next step here is to increase his comfort zone. Most horses prefer to be with other horses, and if there are no other horses around, they will stick close to their handler. For especially timid or spooky horses like Vienna, this could be hard. Leave your horse about half way down the arena or pen you are working in. Say your command (whoa or stand) and deliberately walk away, still keeping one eye on him so that you can correct him if necessary. Walk just outside two meters, which is his previous comfort zone. Then return, walking slowly and smiling if he does not move. If he does, correct him, and walk away again. As soon as he lets you walk farther away, return, praise him, and then stretch that zone again and see if you can get all the way to the other side of the pen.
This will take a while. Be ready to calmly correct your horse billions of times! If you are not very patient, perhaps you should consider hiring us to train for you. Please send us an email if you are having troubles.