Perhaps I can help. I used BT between my tablet and PC as part of a development process for work with BT on embedded system. My PC did not have BT, so I used USB BT dongle. When the dongle installs it is assigned as a virtual serial port. By using device manager, you can find find assigned port. For first test, I used free PC terminal emulator application called TeraTerm, and one called BlueTerm on tablet. With the terminals it is possible to type and get character communications back and forth. This step proves the devices are properly paired, and hardware is working.
For the Android side learning to use AsyncStreams will help getting the communications going there. Erel has provided excellent example in Bluetooth Chat. For the PC side there are MS examples for serial communications using .Net.