See attachments. to upload an image use the symbol in the bar above the writing area (see attachment - “use this”)
Then on next screen navigate to your file (choose file)[1] and then hit upload[2].
As for your issue - see image 3. you may just need to trace a line to recreate a missing face. Turning on hidden geometry may also help show you whats going on because after rounding/softening, geometry gets hidden.
