need guide on how to upgrade house ....

So, wowhead has guide on player housing.

https://www.wowhead.com/guide/systems/player-housing-overview

no mention of how to upgrade your house.

There is a link to decor.

Google search has TONS of resources on where when how to get preview see hunt find decor.

Google search for how to upgrade house is "get stuff", but no description of what stuff, how much stuff is needed to upgrade a house, etc. etc..

Anyone got a written guide, not video, on how to upgrade the house?

Thanks!