For the mic, go to settings > sound.
Make sure your mic is selected as the input device.
And maybe you're not on the correct frequency?
For adding aircraft, there should be instructions included with most aircraft, but:
Place the folder that has the subfolders panel, model and some others, in :C -> Programs -> Microsoft Games -> Microsoft Flight Simulator X -> SimObjects -> airplanes folder.
Gauges and effects go in their respective folders in the Microsoft Flight Simulator X directory.
And make sure to unzip the files to a temporary folder before installing.
