It was not even an interview i would say. A friendly chat that interviewer introduced the company background and the project for the job. You were asked if you liked the job and you are hired. Note: You are very likely to join a project that technical skills totally mismatch your expectation

Just chat with for 30 mins. Mainly talk about how great is the company. And ask you what do you want to write. Nothing about tech. If you said you write Java, then you can never write Java here. Usually, you can write want he promised you.