A command is made up of a command letter (telling you what the command does) and a two-digit parameter. You can look up all commands in the
manual, where every command is described in detail. You can also put the edit cursor on the command and read what it does in the status bar of the program (in this case it would tell you that "2" is a portamento down, i.e. it decreases the sample frequency). If you want even more details inside the tracker, you can double-click the command, where you get a full list of available commands.
