Your uploads can be seen in the monitor window, but I think this is set by default to clear all completed uploads, so you will not see much there!
go to options or preferences>uploads>Basic>Clear uploads>uncheck the box>apply >ok
Then you will see all the uploads that occur in a session until you manually clear them. (I gather doing this uses more computer resourses, but I lke to see what's going on
)
100MB is not a lot in audio terms. it is the size of a good sized album with a decent quality bitrate
By default your shared folder will be your download folder, and so , again by default, any thing you download is imediately available for upload.
The default settings can all be changed in options or preference
Let us know if this helps and if you are still worried.