When an adventurer performs a lockpick check with multiple attempts, how must key digits be matched and how does gaining light fatigue allow adjustment of dice results?

If the difficulty code for a lockpick check includes a key digit (a digit with a spiked border), that digit must be matched first before the adventurer can attempt to match any other digits.
On your first roll, you must keep a die matching the key digit (if rolled) before keeping any other dice.
After keeping a die that matches the key digit, you may then keep other matching dice from the same roll.
Once the key digit has been matched and kept, you may roll that die again in subsequent attempts as normal.

(Source: page 69)

After rolling, you may gain light fatigue to adjust your dice results.
For each light fatigue gained, you may change one die result by 1 (increase or decrease by 1).
You cannot rotate a 6 to a 1 or a 1 to a 6.
This adjustment can be used to help match the required digits, including the key digit.

(Source: page 69)

Key digits must be matched and kept first before any other digits in a lockpick check.
Light fatigue allows you to adjust dice results by 1 per fatigue gained, helping you match the required digits.

References: page 69 (lockpick sequence, key digit rules, light fatigue adjustment)

Source: Core Rulebook (pp. 61, 68, 69, 70)

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