If you are using Thingworx 7.4, binding multiple tags is much easier using the Next Gen Composer. A step by step example can be found in the help center here PTC.
Otherwise, using classic composer will require a more manual process. There is a great example service posted in this community thread.
I have a similar problem. I successfully connected Kepware to Thingworx and I added a tag by using the new composer as described in the guide you mentioned. I get the tags but I cannot get any value... seems like the industrial thing is not connected... Can you help me on that?
KEPServerEx is the industrial connection and TestKEP is the industrial thing.