Hey there! Wow, hank you for the long feedback.
I saw in a tutorial how to use unions, and I used one to make a hole on the Chimney of the house. Despite this, I think I am not totally familiarized with them, so thanks for your explanation!, it will be useful in future buildings.
I donwloaded Blender some days ago, as I noticied many builders here use it. I really haven´t tried to make anything on it. I think I will learn how to use it and start building on it, as you and other people mentioned it has got more features than the Roblox Studio, and maybe start making more detailed buildings. For me, I totally made a mess while i was doing that window with Roblox Studio, and is true that it doesn´t allow you to use gradient colors, just normal ones.
Again, thank you for the long feedback and for spending your time writing it. It will be really useful!