1) i usually start with current mana, because i can use skills to change it, and watch the memory scanner for the changes easily.
2) once you have the address for current mana, subtract 0x78h (hexadecimal) to get the base address for the character stats
3) search for that base address, once you find it subtract 0x0Ch, search, and that will get you S1PlayerStatController.
4) subtract 0x30h from S1PlayerStatController, search, that will get you the LocalPlayer address
5a) from here you can subtract 0x14h from local player, search, and that will get you the main GameManager, then you can find the offset.
5b) do a Pointer Scan, 2 levels deep, and limit the offset to a low number like 0x20, and it should be a very short list, with a TERA.exe+0x14 somewhere in there are your address you want.