How detailed should I learn things?

Hello, I have been using and enjoying LingQ for many months.
I listen to beginner lessons.
I have also been doing a lot of reading.

Sometimes I see inconsistencies in my target language.
Sometimes I have doubts:
Sometimes I’ve seen “hraju fotbal”, other times “půjdu si zahrát fotbal”. How in detail should I learn this? What is the difference between hrát fotbal and si zahrát fotbal?
Thanks

Hi! As a beginner mysef I am not the best person to explain these things but since nobody else chimed in I give it a try. You are talking about verb aspect here, hrát being an imperfective verb and zahrát being perfective. The imperfictive verb indicates a repeated, habitual or unclompletet action. The perfective verb indicates a finished one time action and can also be used for the future.

Hraju fotbal= I play footbal. Often and regulary. I am a footbal player.
Půjdu si zahrát fotbal= I will go and play this specific match footbal. Relating to a single future event.

The whole thing is wholly confusing for me too, still at the moment.
I would advise you to be just aware of the concept and to start noticing it when you are reading and listening. You can also find a Memrise course that teaches the verbs as pairs.

And yes, if you want to learn czech or any slavic language you will have to learn this. Good luck!