Board Thread:Support Requests - Getting Started/@comment-45256847-20200603172823/@comment-9605025-20200603175420

As Tupka217 already said in the other thread, they are using nested tabber tags to accomplish this. Without the use of templates, it would look something like this.

This is quite messy. I would suggest using panels for the higher-level tabs and then using the standard gallery tag method for the final level.