Some discussions and Q/A happened in the Pro subforum, regarding the sheet (thanks to TheJokerPlays, DXWarlock and Statboy), that could benefit to everyone. So here's a condensed version that will probably end up in a revised version of the wiki.
Armor Check Penalty (ACP)
ACP is applied to the skills value from the total Check Penalty, tallied from the individual AC items Check Penalty, if the AC item is checked as “EQuipped”.

Skills having “Apply Armor/encumbrance penalty” checked will be modified by the total Check Penalty, and a penalty icon will appear next to the skill value. By default, every Strength or Dexterity based skill have “Apply Armor/encumbrance penalty” checked.

Note that dropping an armor or shield from the compendium will automatically fill the appropriate AC item properties. These properties can be adjusted to match a magic item, for example:

How to handle Power attacks, Precise Shots etc.
Modified attacks like Power attack or Precise shot can be handled in several ways, like:
Not mentioning, obviously, creating macros from copying and modifying the full roll query from the chat.
“Macro formula”, using character stats, in a roll
As a general rule of thumb, in Weapons/attacks and Spells, or even in any “Notes” that would be shown in a roll (abilities, skills, feats etc.), you can use any attribute of the character. The formula may need double brackets in some case (like in a Notes or Description or a Spell attribute like “Effect” or the Description or Damage Type of an attack).
Handling Sneak Attack
Imho, the best option is to create a dedicated entry in Weapons/Attacks, with no attack checked but only damage (and eventually use Damage2 for supplemental magic damage), to be clicked after an attack that hit and is subject to “Precision damage”.


If you prefer that the Sneak Attack damage be rolled every time an attack occurs, add it as secondary damage :


Or in the Description (or Notes) as an inline roll :


Half-strength and one-and-a-half Strength or Dexterity damage bonus
In the dropdown list of damages in Weapons/Attacks main damages or Aditional Attacks damages, these options are available as “Two-Handed” for one-and-a-half and “Off-Hand” for half ability modifier:

Tracking prepared and used spells
Regarding Arcane spellcasters, the design idea was that the spells prepared would be set by the player, and then decreased as they are used.
For example, this Wizard can prepare 6 spells per day, and has prepared 3 times Burning Hands, 2 times Color Spray and Expeditious Retreat once.

Later in the day, the Wizard has cast Expeditious retreat and Burning Hands twice, ending up with:

Dynamic effects of Spells beyond attacks, damage and saving throw
Every text attributes can contain a “macro calculation” that will be “rolled” dynamically when “casting” the spell.
For example:


So, you can drop a spell from the compendium to fill the character sheet and modify it in this way afterwards:

Rolling Concentration checks
Concentration check can be rolled from the Spells tab or from the Spell roll itself in the chat


Ending in:

Handling special features like the Witch Hexes
Special and spell-like abilities can be entered as class features or Spell-like ability, as you wish and depending on the specific features of the ability. As a general rule, there is no good or bad way to use the sheet, but the one that suits the player.
Example as a Feature/Trait:


Example, as a Spell-like ability:


Tracking “permanent” bonuses from magic items and other sources
All the items' mechanical effect should be handled either in the AC Items repeating section (for armors, shields and other magic items giving protection bonuses), Weapons/Attacks repeating section, or the various Misc modifiers & Notes for the “permanent” bonuses given by other magic items. For example.

Armors or Weapons weight
The inventory repeating section only intend is to list consumable items, and/or items with significant weight to automatically calculate encumbrance. To account for an Armor or Weapon weight, as any other item, it has to be added in the inventory, with its weight.
Note that an upcoming feature will be an universal/facilitated drop from compendium, to add (for example) the dropped armor automatically to the inventory and AC items.

Handling items like Masterwork Backpack, and other modifiers to carry weight
Options are available in the encumbrance section:

Conditions
Every conditions listed in the CRB are available on the sheet:
Blinded, Cowering, Dazzled, Deafened, Energy Drained, Entangled, Exhausted, Fascinated, Fatigued, Frightened, Grappled, Invisible, Panicked, Pinned, Prone, Shaken, Sickened and Stunned have automatic mechanical effects on applicable stats and rolls on the sheet.
If checked, a reddish icon icon will be shown on the sheet, next to the appropriate stats and/or rolls.
For example, a panicked character:

All these stats and/or rolls have been automatically recalculated according to the rules (and thus the derived attributes). This will show in the relative rolls:


Some conditions, like Blinded, Prone or Energy Drained etc., will also show modified stats in boxed in red, or red text, or show additional information:

The other conditions (Bleed, Confused, Dazed, Disabled, Dying, Helpless, Incorporeal, Nauseated, Paralyzed, Petrified, Stable, Staggered and Unconscious) have effects in the way the game plays, to be managed by the GM and players, but don’t have a direct mechanical effects on the character sheet stats & rolls.
Favored class & leveling up
Your can indicate which of the character classes are favored with the “F” (Favored) checkbox in the Classes section of the Configuration tab. A misc field is available to record the total skill ranks bonus gained from the favored class levels gained (and/or from others sources).

As for leveling up, see: https://app.roll20.net/forum/permalink/6881884/