How Do I Create Custom Structure Processors

I am currently creating a mod that adds several new structures. One of these I want to have some random water and lava spawn in it, essentially replacing about 1% of air blocks with either water or lava. I know that minecraft uses processors to do things such as mossify blocks or create cracked variants, and I'm wondering how I can manually go into my workspace file, add in a processor, and then add that processor to my structure. From what Ive researched so far it seems I could use the minecraft:rule processor to create a custom processor but no matter what I've tried it never works. If anyone happens to know how to do this I would really appreciate guidance on how to implement it. Thanks for any help!

UPDATE: So ironically after posting this I figured out how to make this work, the only problem now is that the water and lava that spawns is not flowing and is simply sitting there in one block. How can I update the block so that it spawns in my structure and then flows?