Where is the master key map for all these symbols in the documentation and tooltips?

I have been trying to learn more shortcuts to more efficiently manipulate my documents. In the documentation and tool tips there are all these symbols for the default hotkey configurations. I want to know where these symbols come from and how I am supposed to know what they are. Like what the heck key is  ⏎ or ⌥ or ↑ or ↓ or ⇧ or ⌃

They are referenced everywhere in the documentation for the various products. I don't know about you but these things are not intuitive to me. I don't know what these things refer to. I haven't been able to find anywhere where these things are documented. I am getting tired of trying to guess. I tried googling them but all I've been able to find is the ascii codes for them, not what keyboard key combinations they refer to.

Any help in this department would be really helpful.

Thank you,
Aaron