This is the 5417th most frequent Turkish word.
kurdukları
"Their established" or "what they have built/established."
The word 'kurdukları' is used as a relative modifier, referring to 'kulübe' (the club) that has been established by 'the students'.
Arkadaşlar, öğrencilerin kurdukları kulübe yönelik öneriler sundular.
Friends offered suggestions regarding the club the students established.
Here, 'kurdukları' modifies 'deney' (experiment) and indicates ownership or creation by 'scientists'.
Bilim insanları, kurdukları deneyde ilginç sonuçlar elde ettiler.
Scientists obtained interesting results in the experiment they set up.
In this sentence, 'kurdukları' describes 'iş ağları' (business networks) created by 'the companies'.