In the porch area of the mansion build grass blocks in the area for a nice modern theme to the mansion.
Build the wood on the outline of your mansion, make it as big as you want, I prefer to make the outline of the mansion a bunch of big squares, but connected.
On top of the wood build cobblestone 20 blocks high and build a outside porch area and build a roof for the mansion but leave the porch area open without a roof make sure to make a arch at the entry.
Build quartz blocks on every other block on the arch, and make some pillars around the mansion.
When you are done building the mansion it is time to put some decoration like carpet, lights, music box, enchantment tables, anvils, crafting tables, chests, tables, paintings, and beds, and bedrooms.
THIS IS THE END THANK YOU FOR READING MY GUIDE ON HOW TO BUILD A MANSION IN MINE CRAFT THANK YOU AGAIN!!!