How do I use the colours on the The Fate Deck?

Use the colours for adjudicating outcomes with an even distribution. Ones that are not influenced by a characters ability scores.

SAGA rules refer to this aspect of the card as an Aura color.

A Narrator can use the Aura color of a card to determine the outcome of an action instead of using the number on the card.

Narrators more familiar with dice based games can think of the Aura Color as having the same probabilities as rolling a three sided die (D3).

Each suit has colored the numbers 1-3 White, 4-6 Red, 7-9 Black. Mechanically the cards are divided evenly such that the odds are uniform among the three outcomes.

begin{array} text{Aura/Moon} & text{Values} & text{Symbolism} \ hline text{White/Solinari} & 1-3 & text{Good/Positive} \ text{Red/Lunitari} & 4-6 & text{Neutral/Uncertain} \ text{Black/Nuitari} & 7-9 & text{Evil/Negative} end{array}

The rulebook provides one example for using the Aura Color, that is to help determine an NPC's demeanour toward the Heroes; drawing 'White' could indicate kindness, 'Red' - mysterious, 'Black' - unfriendly.

Using the Aura color in this way means that the NPC has an equal chance of being kind, mysterious or unfriendly toward the Heroes.

Note; the suit of Dragons Aura color for all cards is Black. To achieve truly even probability distribution a Narrator should redraw if they pull a card from the suit of Dragons.

Alternatively, you may wish to include the suit of Dragons as a "mishap" (in game terms) where drawing a Dragon indicates a much worse outcome. Perhaps for the example above the NPC is actively hostile toward the heroes. Using the Fate Deck in this way skews toward negative outcomes, there is a 12% chance a drawn card is from the suit of Dragons.

Chart: Fifth Age Book One p. 54