How do I eliminate an unwanted color?

Greetings,

Please note the attachment. Orange filament shows up for the raft and I cannot move the slider (on the right) low enough to capture it. How might I change it from orange to blue?

Also, in the “Send Print Job” box, does the left-to-right order of the colors shown represent the order of printing? I ask because white showed up as second (after orange) and blue was on the right. I switched the blue and white, placing the blue filament to the left of the white (in the print dialog box) and the white loaded before the blue.

I cannot seem to locate specific instructions for this screen but, if anyone out there knows where to send me, a link would be appreciated. Thank you.