As a d20 system, The Fade Tabletop 2e plays a lot more like The Fade Tabletop 1e, making the change over is not incredibly difficult but does require a bit of reworking of certain mechanics.
Normally, The Fade Tabletop 2e uses rolls of d10s that are limited by an amount of keep dice. In place of rolling d10s, a single d20 is instead.
All rolls (except for damage rolls, more on this later) are done with a d20. Natural 20 is a critical success and natural 1 is a critical failure.
For an Attack, you roll 1d20 + Ability Score + Attack Bonus + Misc
For a Skill, you roll 1d20 + Level + Ability Score + Misc
Each class gains what is known as an Attack Bonus. This is a modifier added to attack rolls based on the skill of the character. There are three bonuses, one for each type of progression, and this progression is linked to Attacks per Round.
Fast Bonus is equal to that of a Soldier (or, gaining up to 5 attacks per round). This bonus is equal to level.
Medium Bonus is equal to that of a Rogue (or gaining up to 4 attacks per round). This bonus is equal to 2/3 level.
Slow Bonus is equal to that of a Mage (or gaining up to 2 attacks per round). This bonus is equal to 1/2 level.
Defenses go mostly unchanged from how they are normally. Parrying and Dodging however function differently due to the alternative dice system, adding a d20 + a stat to a Defense when dodging would be too unwieldy.
Instead, the character can expend a Dodge to add their Agility as a bonus (again) to Defense or Avoid. In the case of Parrying, they can add their Attack Bonus onto Defense or Avoid.
Class Abilities, Feats, Spells, and Monsters all mention the standard dice system (d10), however this conversion should help in the case of altering them to the d20 system.
Bonus rolled dice (+1k0 for example) add a +2 bonus for each rolled die that would be added. Bonus kept dice (+0k1 for example) add a +5 bonus for each kept dice that would be added. The opposite goes for penalties, -1k0 means a -2, and -0k1 would mean a -5.
Flat bonuses (such as: "Gain a bonus equal to level to-hit") function as normal.
Damage in the original system uses the same system as rolling attacks and the like uses. The inclusion of the d20 system alters the damage - which in this case do not use only d20s but instead using an arrangement of dice (from 1d4 to 1d20).
Weapons/Spells: Keep dice determine the die that'll be rolled for damage, and the amount of rolled dice determines how many of these dice are rolled for damage (if multiple are rolled).
Damage is calculated like so;
(Base Damage Dice + Ability Score) d (Damage Dice) + (1/2 Ability Score) + Misc
For example, wielding a Longsword with 8 Strength. Normally its damage would be 3k2 however with the new damage dice system it becomes a 3d6 weapon. The character adds their 8 Strength to the rolled dice making it an 11d6 weapon, and adds half of that to the end bring it to a total of 11d6+4 damage.
Damage is factored against Soak like normal.