Hi @Courtenay_Ennis!
Welcome to the community 
Now that you’ve spent some time with the documentation, you’d be best served by building docs.
What do you want to build? There’s nothing quite like learning by building!
Also, what languages | frameworks are you already familiar with? I don’t know what RDB is, unfortunately.
Some things I have to recommend:
- Search the Coda community for the words “schema” and “structure” and read some of the posts. You’ll see lively discussion on how best to do doc structures.
- Follow @Paul_Danyliuk on YouTube and go through some of his videos. They are really deep
- Stop building a doc the moment you start to get tired of it. Then start rebuilding from scratch. That exercise will help you think about what happened that tired you out. Great for learning
As general doc recommendations:
- Use the same icon multiple times to visually signal doc structure and actions (not page meaning). So, use a mouse pointer symbol for anything related to selecting something, and a magnifying glass symbol for anything related to searching. The title of the page will tell what a page relates to, you don’t need the symbol. E.g.
Select Dates instead of 
Select Dates - Separate your source table into its own dedicated page, where all the columns are visible. Then make everything else a view of that table
That’s all I can think of for now. Play with the formula language a lot, here’s a good challenge if you’re up to it: Holiday challenge!