Files can be imported from most file sharing services. Below is a quick walkthrough using Dropbox, however the process is similar using other apps.
In DropBox, select the file you would like to open in TurboApps.
Next, tap the more button (three dots) near the top right of the screen. (No preview will be available, as dropbox cannot view CAD files)
Now tap export.
Then tap Open in...
Now choose the TurboApps product you would like to view the file in.
The file will then open in the selected app.
A copy of the file will be saved locally in your inbox.
For more on opening files from DropBox and Box watch the video below.