To your question regarding creating symbols, there is another thread from yesterday and today on this topic. However, ACE comes with a complete JIC symbol library, so unless you are itching to spend a lot of time creating symbols, I'd suggest you use what's "in the box".
The location code is added when you instert a device. The insert/edit component dialog box is where the parts information, and there is a box for the location code as well.
Recently, there have been many comments in this forum regarding a User's Manual for ACE. For what I have seen, I thnk that Autodesk is taking this issue under consideration. My humle opinion is that a book like this might be expensive to write and publish, so if we users really want this, we might expect to pay a bit more for a copy of ACE. I say it would be worth it.