The bug has been reported, whether it gets fixed before this goes live is anyones guess.

I've noticed this bug is hit and miss. Some thralls finish and stand next to wheel, I had one wander off and can't be found, but I have had a couple that stayed in the wheel. The fighter allowed me to complete the "place in world" step but I have not found any way to assign a crafter to a work station. Even if you can pick them up from the wheel, it insists you have to place the thrall in the world before assigning. Once placed in the world, you can not assign the crafter and have it count.

Originally posted by AstroBalrog:

After my thrall was finished in the Wheel of Pain, she was standing next to it - I could not pick her up to "place her into the world." How do you finish this journey step?

Please bear in mind that this is the 'Test' server. There will be bugs. Ones that Funcom know about (eg the New Follower perks), and those they don't (plus the ones that Funcom know about, but don't tell us).
Don't waste your time searching for solutions. The full Live release is in 3 days time. If the the problem still exists then make a noise. In the mean time, just play the game and work around the bugs.