Not sure about MP3 maker but other products you simple place the marker in the ruler bar where you want the split, click the desired MP3 and then press T on the keyboard... whola! you have a splice in your MP3.
Justin
MP3 Maker comes with the Music Editor 2.0 as audio editing tool. So, you should load the file you want to edit into that program first, either by starting up the Music Editor 2.0 separately (from the MP3 Maker start-up group created in Windows) or by selecting the desired file in MP3 Maker and using the edit button.
In Music Editor, you have different editing facilities and ways to accomplish what you want to do. You might want to have a look at the online help system in the program. One pretty straightforward and elegant way to slice up a big file into chunks might be by utilizing the track marker feature. You can put one in at cursor position via the "CD" menu. Just set a track marker at every position where you actually intend to end one file and start a new one. Now go to the "File" menu => "Export Audio" sub menu => "MP3" option. This will open the export dialog, in this case for MP3 format. Configure the export destination directory on your hard drive and MP3 quality settings. Make sure to tick the option "Each CD-Track in a file" and start the export process. This will start rendering new MP3 audio files to your hard drive and actually take your track markers into account, thus creating a new file for each marker.
I hope this is the information you were looking for.