Welcome everyone. This is a simple guide to provide information of how most of the bonuses work.
Enjoy! 
HP Regeneration (*):
Increases the % HP regeneration you have. The basic (without any item equipped) HP regeneration acts every 3 seconds and regen your 5,12 % of your HP. Example: If I have 50% HP Regeneration and 50.000 HP, then every 3 seconds the amount added to my HP will be:
5,12% + (5,12 * 50% ) = 5,12% + (5,12 * 50/100) = 5,12% + 2,56% = 7,68% of 50.000 HP is: (7,68 * 50.000 )/100 = 3840
If you move or attack, then your basic HP regeneration is lowered to 1,12% every 3 seconds. Same way:
1,12% + (1,12*50%) = 1x12% + (1,12 * 50/100) = 1,12% + 0,56% = 1,68% of 50.000 HP is : (1,68*50.000)/100 = 840
SP Regeneration (*):
Same with HP Regeneration. Read above.
Chance to absorb HP (*):
From the damage you will deal with a single hit to your enemy, the written amount, which refers to the damage you made, is summed to your HP. Example: If I have 10% and deal 500 damage, then my HP will be increased by 50.
Useful Note: The % refers to the amount of HP you will be given back and not the % you have to actually get HP back. Absorb HP works 100% and always, if you make damage.
Chance to absorb SP (*):
Same with Chance to absorb HP. Read above.
Chance to rob SP (*):
With every hit you deal to your enemy (not monsters), you take away 50 SP from your enemy. The chance you rob 50 SP with every hit is based on the % chance to rob SP you have.
Attack Speed:
Increases your attack rate per second, with a cap of 200. Above this amount, there is not a difference.
Poison Chance (*):
Chance to poison your enemy or monster with a hit or a skill. The HP which will be abstracted from your enemy equals to 5% of his total HP. You can poison your enemy only if the level advantage is above or equal to 6 (same for monsters). Poison abstracts 5% of enemy's HP always 10 times.
Chance to avoid Arrows (*):
Works on monsters that hit you from a distance (range/mages) and on ninjas that hit you or skill you with a bow. This bonus will increase the chance to receive 0 damage from your enemy (miss).
Poison Resistance (*):
If you get poisoned during a PvP or from monsters, then your HP will be lowered by 5% of your maximum HP every 3 seconds. What poison resistance does is to lower this % hp that is abstracted, based on the % of poison resistance you have. Example: If I have 20% poison resistance, then the % HP that will be abstracted when/if I get poisoned by an enemy is equal to:
5% - (5*20%) = 5% - (5*20/100) = 5% - 1% = 4%
Chance to reflect close combat hits (*):
When you are getting hit by an enemy which makes actual damage, the % written in your bonus will return as damage to your enemy. This bonus works as a mirror.
source: metin2 wiki
(*) : Means that this is a percentage amount and not an actual amount.
Best Regards, Factory Team