Broken file mcworld association with latest release

I've just installed Minecraft Java Edition, the file assotiation to mcworld had not been created.

I would like to play alien-invasion from you page. I've tried to accotiate it with Minecraft Louncher, but after doing so, game start but on default world.

How do I fix a missing file assotiation?

Why there is not import option inside a game

I have 1.13.2