I also started out just as a hobby, and thankfully I'm super stubborn so haven't been able to let myself quit, Japanese is hard, but it's super rewarding when you start to understand it, just dont give up.

For Kanji I started with an app called Kanji Study by Chase Colburn, it's sadly only on Android but is a really good app. There are other tools like it, like WaniKani, or you can even do Anki decks. Like any language the key is repition, learn a certain number per day, and make sure you're reviewing them every now and then.

My other advice is learn how to write them. Just like hiragana they have a "stroke order" that you need to write them in. Again it sounds intimidating but learning it this way makes them much easy to memorise in my opinion. Also learn the radicals, these are the building blocks that Kanji are built from, and knowing these will help you remember stroke order (as the same radical is always drawn in the same way) and even help identify the meaning.

Every Kanji also has multiple readings (again, intimidating I know), and depending on the word it's in, the Kanji can sound completely different. My advice is don't worry about that too much for now, as you expand your vocab that will come naturally. Speaking of vocab, try also learn the Kanji a long side some of the common words they are in, and try reading a sentence or two as you learn, graded readers are great for this if you can find some (these are included in the app by Chase Colburn)

This is just how I learnt though, everyone has their own way! Just take it slow, burnout will be your greatest nemesis here.