First strike/ Double Strike

[Yhisper]

i am new to mtg and the concept of first strike and double strike confuses me, how does the damage work with first strike with the damage delt before other damage, and then with double strike how does it exactly work?

[Kaylesh]

i am new to mtg and the concept of first strike and double strike confuses me, how does the damage work with first strike with the damage delt before other damage, and then with double strike how does it exactly work?

Normally, creatures that attack and block deal their damage at the same time.
When a creature has first strike, an extra damage step is included, in which these creatures do damage.
So, they do damage before creatures without first strike.
After the first strike damage step, creatures that have received lethal damage (equal to or greater than their toughness) die, these will not deal damage during the regular damage step.

example:
{advance scout} attacks, and is blocked by {raging goblin}. The scout has first strike, killing the goblin before he can do damage to the scout. So, the scout lives.

In the case of double strike, a creature will do damage both in the first strike AND in the regular combat damage step.

[Kaylesh]

Long story short. 

If I have D-Strike and Trample, if I kill the creature on the first strike damage, i don't deal the regular damage.

However. If a 0/1 indestructible was being attacked by my 2/2 d-strike trample, I would end up dealing 2 damage to the player. The way trample works is that you assign enough damage to kill the creature and whatever is left over is hit at the playa

Short story is incorrect though.
If a creature with trample is blocked and all creatures blocking it are removed from combat by the time damage is assigned, it deals all damage to the player. If you attack with a 5/5 double-strike trample, and I block with a 1/1, 9 damage is dealt in total to me.

Even your second example is off. When assigning damage you just look at what would be lethal, without considering what damage is prevented, or any other abilities.

[Kaylesh]

Lol my bad. I 100% thought that was correct. That's what I had always been told. Whoopsie. Thanks for the karma however ;-)

NP. I happen to know because about a year ago I too thought no damage would be dealt.
It's how we learn, by being pointed out mistakes.

EDIT: the negging was not my doing by the way. Only just realized what you were referring to due to tiredness..