I dont get how to use it >< (the mask and Re-mask)

Most people don't know how to use it.. I didn't know until a week ago or two..

Mask- The specified color will be untouched and the space around it will be colored.
Re-mask - Only the specified color will be colored.

To select the color used for masking or re-masking, you choose the color, then back click (or right click) on the 'mask' or 'Re-mask' button. The default color is black, but it can be any color you want.

This is what I think I know.. Not too sure yet. I hope this helped a bit.

Thankyou