Hola,
This lesson is clear in distinguishing the Futuro Próximo, but is there a reason why none of the translations offered use the variation "I am going to buy a house.... / They are going to have a meal tonight.... etc.?
These would be common ways of expressing future arrangements in English, and happily distinguish it very clearly from the present progressive "I am buying a house" which doesn't quite capture the idea of a future arrangement.
Is there some distinction that I'm not aware of?
Saludos. John