how much life do I gain in magic if lifelink 6/6 attacks and 2/2 creature blocks

[Secret]

if a 6/6 creature with lifelink attacks a 2/2 creature how much life do I gain?

[Arix]

The lifelinker deals 6 damage, so you gain 6 life.

[kip]

also note u dont attack a creature directly you attack a player or planeswalker and he declares blockes

so like u cant go say i attack the 2/2 creature with the 6/6

but u say i attack player or i attack planeswalker with 6/6 creature

and then player says i block with 2/2 creature