You will need to load a program to do this – the one I use is http://www.applicationscityapplication.com/8EVKCVVUToQNIUpbCVNiPsb0UMJLpSszNlRlZoJLk1ytuLgkhH+Dk1wAEnkvVbBK_L5oZl+sVWStvWtBkk9xfU7T4W5WdbFIonTFG10y9c5ffWjAYDmLSfcANnZITCj3eQMx+wDiBCG_WicwZodbbs9wOZzSvOs4eslR3hb26E0QfZ_UeSnm6ObdSrPY9KeyhclvykyjTYzCns1TKTYrM8yxcGnsQQ==-GzAAAMRtbD7PaUzHinBGEQXBRA4cWkRd6E1tHcgbYzSEZ7dGXVqZJ+lTew29AA==-e
Pay attention while installing it so it does not install any crap ware.
When you run the program you can pick an area, a display or a window. It has some detailed setups to record the video in different formats with different codecs. – Save the file to a directory of your choosing.
To share the file with others, I recommend youtube although it is pretty easy to share on Facebook these days.