Hey Kati. One of the things to keep in mind when learning Portuguese as a native and/or fluent Spanish speaker is that even though the two languages are very similar, they are also very different. It's very easy to shift from Portuguese to Spanish when in doubt, however, you may place yourself in an awkward situation if a word and/or phrase is said and presents a completely different meaning. I would personally recommend getting used to the spoken language first since it's much more different than the written form and the nasals, which are not part of English or Spanish. These nasals present huge struggles to both English and Spanish speakers and are a must for both groups since they are a fundamental part of the language. There are plenty of comedy channels on YouTube in Portuguese to help you get used to the pronunciation. Hope these rather obvious tips evoke some sort of assistance and good luck!

Hola, Kati. ¿Todo bien? Lo ideal es empezar con la música y también ver una película, novela o documental que está en portugués pero con subtítulos en español. Así és mejor asimilar las diferencias y similitudes. Buenos estudios y feliz año nuevo :)

Hello Kati, I think if you watch movies with a portuguese subtitles and a spanish audio you can link words and with portuguese audio to listen how to pronounce and understand better... but the grammar is not simmilar

Have you had a look at hackingportuguese? It's a blog about resources for learning Portuguese. There are a few articles about learning Portuguese for Spanish speakers.

Lo mejor es escuchar canciones. Pero ojo con los falsos amigos!