I have this monster http://www.orcpub.com/dungeons-and-dragons/5th-edition/monsters/wolf Hit Points11(2d8+ 2) does he have 11 Hitpoints or do i need to roll a 2D8 to calculate his hitpoints?

He can either 1) have 11 HP or 2) you can roll 2 8-sided dice and add 2 points to determine the HP. This is determined by the DM.

When my ranger rolls for damage he just rolls a single 1D6 which is just a six sided dice right?

Hit dice are determined by the weapon you're using. Assuming your Ranger has a Shortbow then yes it's a 1d6 for damage. Check PHB page 149 for more weapons.

First I have to roll a d20 to make sure i hit , I roll a 15 so since the wolfs armor is 13 i hit. Now I roll a 1D6 and it shows 3(for example) do i add +2 to it for my proficiency bonus so that would be 5 damage?.. The wolf has 11 HP so do i take off 5 or 3 points from his health.

Only add your Proficiency to hit. Depending on the weapon, you add either your Strength or Dexterity mod to damage. A bow, since it is a ranged weapon, uses your Dexterity mod. You rolled 3 so you deal 3 damage. If you have a Dexterity mod then you will add that number to your Shortbow's damage.

PART 2 So the wolf is 2d4 + 2 damage .I am doing a encounter and I rolled and got a 8, 4 from each dice so now i have 2 hitpoints left from 1 monster WTF. Unless i did it wrong

To clarify: the wolf rolled 8 damage from the dice and then added 2 for a total of 10 damage, correct? That's how you would calculate the wolf's attack, but first the wolf must roll to hit just like your Ranger. Roll a d20 for the wolf's attack to see if it hits you. If you the wolf's to hit roll is equal to or greater than your AC (Armor Class) then the wolf rolls damage.