This is the 10157th most frequent Turkish word.
başlandığında
"When it is/was started."
Here, "başlandığında" is used as a temporal clause marker, referring to the time when the action of starting the project took place.
Projeye başlandığında herkes çok heyecanlıydı.
When the project was started, everyone was very excited.
Here, "başlandığında" indicates the initiation of the film as a contextual marker for the succeeding event.
Film başlandığında salonda sessizlik oldu.
When the film began, there was silence in the hall.
In this sentence, "başlandığında" connects the starting of sports activities with a recommendation to monitor one's health.