Build
So when it comes to League, I am very ignorant. Like, I am a complete noob. But anyway I would like to ask a few things.
That is builds. I am a mid lane main, and I usually use 2 builds. 1 is the normal build your SUPPOSED to go for that champion, the other one is crit.
Normal build being
items like that. Crit build being

Now where I am confused is which build I should be taking in certain situations. Which build is overall better to go, or in specific match ups. Like I said I am very ignorant so if someone could help me with this it would be much appreciated.
but not always. I go crit on many other champs as well