This is the 14291st most frequent Turkish word.
okuldaki
"Okuldaki" means "at the school" or "in the school."
Here, 'okuldaki' is used to describe 'arkadaşlarımı' (my friends), specifying that the friends are in the school.
Okuldaki arkadaşlarımı çok seviyorum.
I love my friends at school very much.
In this sentence, 'okuldaki' is used to modify 'öğretmenler' (teachers), indicating their association with the school.
Okuldaki öğretmenler çok yardımcı oluyorlar.
The teachers at the school are very helpful.
The usage of 'okuldaki' here specifies the location of 'etkinlikler' (activities) as being associated with the school.