I highly recommend joining Croaticum for learning Croatian. You can take lessons online. I’m doing them right now and they’re fantastic. It costs 700 euros for the 15 week course but you get 2h15m of class every week day, which ends up being around 5 euros per hour for instruction.
This course I made is the entire dictionary of the first level textbook. I’ve found it much easier to memorize words alphabetically instead of in groups (animals, foods, kitchen utensils, etc.). The textbook is also very good as it’s written entirely in Croatian. The illustrations and pictures are a little corny, but its got lots of great stuff to practice, even if you’re just doing self-study.
I’m going to go back through it soon and do some editing to mark which verbs are perfective and to expand the definitions of words since the whole “alt” system is kinda broken and useless at the moment IMHO.
There is an awesome BCS textbook and associated Memrise course on here, but I found it difficult and a little hard to just be learning like 15 different nationalities (which have male, female, and plural variants) right away in the beginning just because they’re in the first couple lessons of the book.
What the BCS book does well though is it has emphasis markers for all the words in the book which is invaluable if you’re not learning in person with a teacher who can correct your pronunciation.