Totally agree on massive input without necessarily trying to understand! Somehow your brain will eventually understand, and that's what allows you to have fluent output. If, however, you treat it like a math problem (ok, noun + verb --ok, conjugate it--, ok direct object mmmm) it will be really hard to be fluent, even if all the words you use are correct. So don't practice that way either! Practicing that way means you'll speak that way, and NO ONE will understand you.
Our brain learns phrases--whole phrases--and that's what allows us to speak. People who speak to you are not going to say "Vivo......en......Mexico." They are going to say "vivoenMe xico". The sounds are going to blur together in places other than the spaces between the words. So if you're set on learning words, you will not understand what they are saying to you, and if you say words to them (rather than phrases) they are not going to understand you.
I'm saying this as a bilingual person who lives in Mexico and has lots of experience not being understood at first. :)
So for conjugating verbs, you need to learn each conjugation separately in an organic way.
You'll learn "Quieropastel". And you will learn it totally separately from
"Tegus taria pastel?" Unless you want to sound like a robot and try to pretend that language is math.
Learning language this way will also prevent you from "language interference" which is when you try to directly translate, word by word, from english to spanish, and end up saying things awkwardly.
For example, if I were directly translating from Spanish to English, I would say:
"I have 32 years". Instead of I'm 32 years old.
Will an english-speaker understand? Maybe. Probably depending on context. How much better to just learn it organically though.
In my own journey, I've found that learning some vocab and grammar was enough to get me speaking (terribly) to people so that the INPUT could start. I would listen to what people are saying, and catch a turn of phrase, and think, Oh, so that's how you say that!
In English, for example, there's a million ways to use the word get: get laid, get something from the store, get a concept, etc. Looking that up in the dictionary is going to be hard. Hearing someone say in conversation, "Do you get it?" and the context is "Do you understand?" is going to make your brain say, Oh! That's what they mean! And then next time you're out and about, your brain will say for you "Do you get it?"
tl;dr: Stop thinking, let your brain do it. :)