Watching basic communication-based videos on YouTube will also be a good way to equip yourself with some basic Spanish usages
You can volunteer and take the first step to make friends with the bilingual vendors and the native people there to build your vocabulary
Use apps like Duolingo or Babbel that can exercise your brain muscles with the right amount of linguistic activity you need.
There are so many audio courses available online that can help you with even the most basic vocabulary and grammar.
During your homestay in any Latin American country, look up online for classes that offer Spanish lessons