It's rather straightforward - we only need to create the going to sentences like the pattern in the first one shows us.
Answer:
We are going to decorate the garden for the party
We are not going to decorate ...
Are we going to decorate ...
Andrew is going to cook spaghetti tonight.
Andrew is not going to cook ...
Is Andrew going to cook ...
The kids are going to be ready soon.
The kids are not going to be ...
Are the kids going to be ...
Mark is going to visit a museum tomorrow
Mark is not going to visit ...
Is Mark going to visit ...
