I can recommend Satori Reader, too. Admittedly, I don’t use it as often as I should, but when I do it’s really valuable. I’m currently reading the Zama murders story (which did actually happen) which, for being essentially a baby Japanese text, is still sort of interesting unlike some other beginner material that I’ve seen.
That said, I only started deriving much value out of it once I already had some vocab and grammar under my belt (currently I’m in the middle of Genki 2), before that I found it a bit too tedious.
When you are looking things up, reviewing grammar points, and so on, you are not “immersed.” At least not until you’re fluent enough to use a Japanese-Japanese dictionary.
So you shouldn’t feel like you have to do what was defined upthread as “intensive immersion,” where you diligently try to understand and make note of every unknown word. That’s hard work, not particularly interesting, and will require a lot of non-Japanese tools at the beginning.
Expose yourself to Japanese media of all kinds. Make note of the words you recognize and pat yourself on the back. Get used to the grammar structures. If you notice an unknown word that repeats frequently, look that up, and notice how adding just one word improves your understanding of the text.
Think about why you want to learn Japanese in the first place. Do that thing with as much Japanese content as you can manage. Over time, you’ll be able to manage more, and it will be less like work and more fun, which will motivate even more learning.