How to make a first group?

[sangwon6785]

Captured video is a little bit confusing to me...

How can i make a group?

I just downloaded extensIon and state is like below. what should i do next ...?

[billgoo]

It's simple that you can just drag the "code1.py" and drop that tab title on the "code2.py" which would make a group containing both "code1.py" and "code2.py" in this window.