I mindmap a lot. For complex projects, I find mindmapping especially useful, because I can visually break down tasks to a granular level. I use freeplane for mindmaps.
I discovered that you can copy and paste your tasks from freeplane (the mindmapping software I use) directly into Asana.
copy the nodes in the mindmap and paste - Bam. They turn into tasks. The Child nodes from the mindmap even turn up as indented text in Asana - so you can recognise subtasks. Multiple-select and drag them into a task as sub-tasks.
Mindmap to spreadsheet to Asana
Freeplane allows you to export the mindmap as a spreadsheet - if you like a record of all your tasks in one. Just copy the rows and paste them into Asana - and they all turn up there perfectly.
Now, here’s the freaky thing. I scrolled down to discover that Asana had created an image of the spreadsheet rows that i pasted.
So, you have that for reference as well