right click on the game (TOTK) in ryujinx, click open mods folder, it should open into %appdata%\Roaming\Ryujinx\mods
drop the 30fps folder right into that folder, it should be Ryujinx\mods\contents\0100f2c0115b6000\30fps\exefs\1.0.0.pchtxt
HOWEVER you shouldn't actually install the 30 fps mod, its kind of a shitty mod that does it wrong (tweaks link to move slower and other bad side effects).
Instead, use nvidia control panel on ryujinx to turn vsync off and set FPS cap to 30. Then turn vsync off in ryujinx as well. That apparently runs it really, really rock solid 30 fps with minimal texture issues. People who have put in a lot of hours also mention something about the memory system config tweak to make it run without crashes later on.
I'd still just wait, I've seen people reporting now it runs even better under yuzu with patches and stuff, plus people have started making prebuilt full shader caches (gigs in size). You can follow along on gbatemp or this subreddit
www.reddit.com
I have the digital and collectors edition already preordered, just ran it on PC to fuck around and see how well it runs and its kinda cool after just a few days now (and still 10 days before release lol) it is running really, really well.
One thing is while the game may run with other firmware you apparently really should be running 16.0.2 inside the emulators.