If you’re just starting in Japanese, then I’d still start with grammar now simultaneously. I used a textbook (since it doesn’t really matter if you get an older edition, you can usually find used copies of the popular Genki books for $8 USD or less). If you need free, a lot of people recommend Tae Kim’s Guide to Learning Japanese or Cure Dolly’s Japanese from Scratch Youtube videos. If you’re a Pokemon nerd like me, Pokemon Grammar is also worth checking out.
It’s also good to start practicing listening to Japanese if you aren’t already.
For shows, I watch either on Netflix (would cost money but you might already have it) or Crunchyroll (again, subscription). You probably would want to start with English (or your native language) subtitles at first, but try to really listen to the spoken Japanese and pick up words.
A list of some Youtube channels that might help you is a helpful, but possibly overwhelming list of useful Youtube videos.
There are also some great pocasts out there! A lot of people recommend Nihongo Con Teppei . He has a special Spotify list for beginners: Japanese podcast for beginners (Nihongo con Teppei) | Podcast on Spotify.
Hope that helps!