Exporting to after effects

I do not own Harmony, But I have used the program in trial.

How do you export to After Effects?

File>Export>movie

From the same menu you can also export it as a SWF file which will work as well, or you can attach write nodes and export layers individually:

https://docs.toonboom.com/help/harmony-16/premium/export/render-write-node.html