Unless this is some new installation method I’m aware of that’s not how you install them. If you look at the folder that ‘Official’ is in you should see another one called ‘Community’. Extract your livery there.
The folder structure of your addon should look something like:
D:\MSFS\Community\{addon}\manifest.json
If you can see the ‘manifest.json’ and ‘layout.json’ files at the level in the path I showed above, substituting your MSFS location, then it should work.