The icons at the bottom are:

LOAD - load a file, doing this deletes any current data
SAVE - save your song/video to the hard disc
DELETE - delete a file from the hard disc
INSERT - insert a file into your current song . This doesn't delete your current data.
JUKEBOX - allows you to choose a number of songs, which will be played with full-screen video in the selected order. Useful for demonstrations and parties.
Create New Folder - allows you to create a new folder on your hard drive.
SAVE SONG AS 'WAV' FILE - records the current song as one big 'wav' file onto your hard disc. You can then cut this onto recordable CD, convert it to MP3 using an MP3 encoder or use it as a Windows(tm) sound effect.

MTV files - these can contain song and video data.
'Wav' files - these are the standard PC sound file format. You can record or download wav files from the Internet, and put them into your song.
'Bmp' files - these are the standard PC image file. You can put your favorite photos and images into your MTV Music Generator videos. There are many shareware graphics programs available to convert to Bmp files from Internet standard formats such as 'jpg' and 'gif'.
'Jam Template files' - these are setting for the jam sessions.

By default, clicking on an MTV file will load in all the video and music elements. However, you can load in individual riffs or clips. To do this, right click on the elements list which will appear just before the file is loaded. Turn off the 'song' highlight and you will be given a list of all the riffs to choose from. Turning off the 'video' highlight will give you a list of all the clips to choose from.