having the files in your sketch directory is fine. It normally saves new files this way, cut and paste them into the libraries folder if you want it for multiple projects. ( you said they were already there. )
Library's added wont add tabs to the IDE
You need the library header included in your sketch (.pde /.ino ) file.
If you leave the .h and .cpp in the same folder as the sketch use
otherwise if you move them to their own folder in the Arduino/Libraries folder use