You can add Highnote as an app in Dropbox. To do so, go to Dropbox’s App Center and to the Highnote page:
From there, click Learn More then Connect Account. Connect Highnote with Dropbox by choosing Allow.
Once you click through, in Highnote, click Continue which will bring you to a file picker where you can choose audio files to add to Highnote. Choose an audio file and click Choose > either choose a Space to add this audio file to or click New Space > Import.
You can now see your audio file in the Space of your choice. Additionally, an option to Add from Dropbox is now available on all your Spaces.
Please note, to disable or remove Highnote from Dropbox, go to your Dropbox account settings.