(Fortnite Rescue the World) Build Level 2 Building?

Do not play long Save the world and build 50 Level 2 buildings in one mission. Unfortunately, I do not understand what I'm supposed to do on the internet.

If you have built a wall there's a level of 20 of the material you have to do 50 times
Luke

I did that but the counter did not go up

Do you know how it works now? Because there's nothing else.

I would appreciate an answer.