Hello!
You can try with the futures forms, as a Spanish native speaker I don't know what order you can study, I would recomend you to read books as you will learn the way we talk in Spain, don't read books that's been writen in another languages, read Spanish authors, well, I'm from Spain so I can tell you about Spanish authors, but you can read from other countries where Spanish is mother tongue.
One of my favourite authors is Alicia Gimenez, she has writen the stories about the detective Petra Delicado, if you like thriller and stories about crimes.
I'll choose a book writen in Spanish, not translated into this language.
And if you like Spanish cinema, we have good films like Ocho apellidos vascos, this maybe is a little bit hard because they have different accents from Spain, but is hilarous.
Or watch TV Series, I highly recommend you La casa de papel, is simply the best!
In my chase I learned two languages since my childhood, I didn't studied grammar until I was bigger, maybe until 6 or 7 years old and it was really basic, so I think the best way to learn our language is listening a lot and reading, I know our grammar is difficult, even for me that is my mother tongue! For this reason I prefer to learn the language as how they speak.
Hope it would help me, if you have doubts send me a message
Hasta pronto!