I'm pretty ignorant about configurations in general. Followed the Yeti documentation, which says:
you first need to make sure that Arnold will be able to find the appropriate binaries, to support rendering in both Maya and standalone you will need to set MTOA_EXTENSIONS_PATH to point to the plug-ins directory so MtoA can find it upon initialization. You will then have to tell Arnold itself how to find the Yeti plugin by ensuring the Yeti bin path is set in the ARNOLD_PLUGIN_PATH environment variable.
I set both Environment Variables and Arnold didn`t shown the hair I created.
There`s something I`m missing?