Hi Tim,
You just load the channels. 1 will use 3 when it has an graphic or animation that has an Alpha channel embedded in the file (ie it is a 32 bit file instead of a 24 bit file).
Note that the switcher defaults to using the "media wipe" for channel 2/4 but you just select channel 1/3 in the GUI or by holding down the Media Wipe button in the Trans Area and using the PST bus to select the the M1 source (when it turns blue on the row).
Les
#Carbonite