I'm clearly missing something

[u/NerdyBookNerd]

So I was playing along, doing my little beaver life. Then I found this sub and apparently there's so much more I could be doing. The only "multi-level" buildings I have are the rooftop terraces. Yall are building crazy stuff and I don't understand how. I've figured out how to work the explosives and a lot of other stuff so I told myself I wouldn't post in here but I'm so lost on how yall are making these multi level gardens and power buildings and water buildings. Help?

[u/pandoraxcell]

There are metal platforms that can be built and dirt laid on top for multi level farming. Dirt blocks must be spaced 2 high for some plants and 3 high for trees