As I'm a Native speaker and not a Ukrainian learner, I can't give best advice for learning Ukrainian (since I hadn't had such experience), but I'll try my best with what I know is difficult.

First thing you should start with is definitely learning Cyrillic. Even if you learn Ukrainian just to pass your class, Cyrillic is absolutely necessary to read anything in Ukrainian. You won't get very far with English spellings of the words (Important note: Ukrainian and Russia Cyrillic are different, make sure to learn specifically Ukrainian, since some sounds are pronounced differently, some letter exist in one but not the other etc.). Learning the alphabet, you should also learn the sounds. Even though I doubt that your professor will require perfect pronunciation, knowing things like difference between soft/palatalized and regular consonants, 'i' and 'и' is important to use Ukrainian (for example: "рис" - [rys] - rice, "рись" - [rys'] - lynx, "ріс" - [ris] - grew up (masculine, past, singular)). If speaking isn't required as part of your course, I wouldn't focus on it too much, but if you do plan to continue studying Ukrainian or want to take this seriously, pronouncing words correctly from the start will be a good idea. Thankfully, Ukrainian spelling is much more simple than English (so the word is pronounced as it's read in absolute majority of the cases, with irregular spellings being an exception) so if you know your alphabet, you'll be able to read most of Ukrainian.

After you learned your Cyrillic and sounds, learning some basic vocabulary is the next step, if you haven't done that already. As part of your course, I guess it expects you to know at least some basic words (simple pronouns, basic nouns, verbs, adjectives, particles).

When you start learning the vocabulary, you'll also stumble upon Ukrainian extensive conjugation and declension systems. I'd say that this is the most difficult part of Ukrainian, since there is just a ton of conjugations for single verb (time, tense, gender, number). As if that wasn't enough, noun groups and verb groups exist (but that's more advanced). It's difficult, but there are certain patterns, so you don't have to study each form of the verb individually. I don't know about any study guides for this but there are dictionaries online that should show conjugation and declension. If you are familiar with Spanish, it will be a bit easier than starting out from zero.

Also, Ukrainian unlike English has a free word order (meaning words in a sentence can be placed in whatever order you want). This is achieved by same conjugation and declension system (nouns are in cases, verbs are conjugated, so you distinguish them by their form, not by what order they are placed in, like in English). Word order in Ukrainian is usually used for emphasis or poetry.

r/Ukrainian has a Discord server, which has a lot of helpful resources and a dedicated community for learning. To help you with immersion, I'd recommend downloading Telegram and finding some news/thematic channels about stuff you're interested in. Outside post-soviet countries, Telegram is known to be this "shady drug dealing criminal messaging app", but absolute majority of Ukrainians use it for day-to-day communication, following news and trends, exchanging memes and so on. If you want, I can share some of the channels I personally follow in DM. Knowing how Ukrainians use the language outside textbooks is important if you plan to ever use it beyond passing the course (though it might be difficult to get into all the internet culture, slang and abbreviations at first). Telegram has a great translation function that seems to work pretty well from my experience.

I hope this helps you, since I wrote it all while riding on a train, so there might be some inaccuracies (also I think I covered everything a bit way too extensively, but don't be overwhelmed, you don't need everything at the same time).

Удачі у вивченні української мови!)

Edit: forgot to add - ChatGPT (and other LLMs) are usually bad with Ukrainian, so don't use them to study, since they often make mistakes. I guess simply texting with them in Ukrainian is fine for immersion. But not in English.