Dumping Your Game
One of the most important (and most lamented) prerequisites for BOTW mod management is to have a copy of your game ROM on your PC. For emulator users (Cemu, Yuzu, or Ryujinx), this is usually already the case, but for console-only players it can be more difficult.
You must have a modded/hacked console to dump your game. If you do not have a modded console, you cannot legally acquire a game dump to use with UKMM.
UKMM supports only the latest version of BOTW (1.5.0 on Wii U or 1.6.0 on Switch). Supported formats include:
- Unpacked MLC
or RomFS 
dump - WUA (aka ZArchive, Cemu-specific)
NSP and XCI support for Switch are possible eventual goals, but in the meantime if your dump is in one of those formats, you should unpack them. Yuzu and Ryujinx both have options to unpack the RomFS. If you don't use either of those, check GBAtemp, as the tooling for ROM format manipulation has changed too many times over the years to recommend a specific option.