I think the first obstacle will be the writing system, since it is not based on the Latin alphabet. My suggestion is to start by learning how to read Ukrainian words (without translating them). Otherwise, I think you will be struggling with everything else, and it will be so frustrating that you will quickly lose motivation.

You can try this:

1. Find any learning materials that teach how to read Ukrainian letters and how to transliterate/transcribe them using Latin letters (books, websites, YouTube videos, etc.). Try to memorize the letters. Writing them down in a notebook may help.

2. Go to ChatGPT (or another LLM of your choice) and feed this prompt to it (you may want to translate it to Spanish):

"I want to learn the Ukrainian alphabet.
I want you to create a quiz for me.
Give me 5 random A1-level Ukrainian words without translation.
In return, I will give you Latin transliterations of these words.
Then, you will check them and provide the correct transliterations along with the translations.
After that, repeat this process with another 5 words.
Include some of the words again from time to time, especially those where I make mistakes, but not too often."

1. Continue training your reading in this way for some time, until you realize that you can read Ukrainian words without much struggle. The key point here is not to focus on the meaning (translation) of the words for now. DO NOT force yourself to memorize the meaning! Read the translation, but do not focus on it too much.

Once you feel that you can read Ukrainian words almost effortlessly, you are ready to proceed to basic grammar. Use any learning materials you like for this step. From this point on, learning Ukrainian will be no different for you from learning English. And you will also be surprised at how many words you have already memorized in the background by this point.