Wegen guter Leistungen bin ich zur Teamleiterin Buchhaltung befördert worden.
The above sentence means: Because of good performance, I was promoted to team leader accounting.
I know " war" is a conjugation part of " sein" and we can utilize it in place of English word "was".
However, I don't know about worden. I don't find it in conjugation website. There is "geworden" that is conjucation of "werden" .
Could someone please tell me " worden" is conjugation of which verb? How can we understand when to use " war" and " worden" to say " was" ?
Thank you for your help :)