This is the 178th most frequent Turkish word.
başlayan
"Başlayan" means "starting" or "beginning."
Here 'başlayan' is used as a participle to describe the team that is starting the project.
Yeni bir projeye başlayan ekip çok heyecanlı.
The team starting a new project is very excited.
In this sentence, 'başlayan' describes the event that has commenced.
Başlayan etkinlik büyük bir ilgi gördü.
The event that started received great interest.
Here, 'başlayan' refers to the work that has begun, acting as an adjective modifying 'işe'.