How do I place custom temples/structures when generating new chunks?

I want to make a custom temple that spawns in chunks similarly to how monster spawners do.

How would I make a custom temple, how would I make it spawn, and how could I make it have chests that take from a loot table to fill randomly?

 

If you want to add this to a default world generation, use a WorldCreator and then get the chunk generator and add your custom BlockPopulator (I believe you can do that). In your BlockPopulator is where, using a percentage chance, you generate the temple. BlockPopulators can be buggy and sometimes stall the generation and will crash the server while generating. I forget why. This has been a crash course

 

I can't find anything about how to create a custom blockpopulator online, I can only find how to use premade ones (trees, ore, etc). Do you know of any examples I can look at on how to create one?

 

@ElkTF2 I didn’t use a blockpopulator when generating my structures. Here’s my explanation/code