This topic is well discussed, but still unable to sort this out on my design.
I have added a new ground symbol to the library - CHGND_MTR. In my schematic I cannot chose this as an alternate ground symbol. But it does show when I open Ground Off-Page types in the part editor. Then if I chose Tools->Update from Library, this ground symbol changes to the symbol for AGND in the lib. How do I rectify the library, what can be selected as an alternate, and what is in the design.
Now for power symbols. The default starting schematic appears to have a single symbol called +V, with no net assigned, which I think is perfect since I'll be able to assign to whatever net I want and not get symbol/net mismatch errors. How would I go about deleting all of the existing special symbols in the lib (I think I can do this part), and transfer that to the schematic? I'll have a challenge making sure all maintain all nets and don't break something I suspect.