The 3880 uses an 8 channel printhead. The printer takes 9 cartridges but the last 2 (Matte Black and Photo Black) are actually 1 channel which is subdivided from 2 lines.The 9nth channel can never be used for an extra color. The cartridge needs to however just sit in and be installed.
In Acro10 , you can set up the ink sequence per your choice as it has Custom channel settings feature in it but still many customers choose to use the standard/Old way for the ink sequence.
Here below is user(s) feedback on how they prefer to use their printer with Acro10 software-
Can be setup two ways
3800 cartridge configuration is KCMY+WWWW
Can be setup to use 3880-3885A print engine - xKWWCMWWY
Don't use matte black , you can fill the 9th cartridge with K or can leave it empty
That setting will allow color and white ink printing.
Customers depending on the results they are looking for use the color settings, some use 1440x720 on both color and white with ink % on higher side(though for DTF printing we recommend low ink%) and some use 1440x1440 bidirectional aprox 35% C and 40%W to start with medium+large dot size for getting the desired results. You will need to adjust the settings according to the logo/design you are using to print.