Some armour rune help :(

Ok, so, here it is...quick amd simple

my hood has +1 Scythe mastery, (stacking)
I have a rune to give +2 Scythe mastery (non-stacking)
if I add the rune to something, will I have +2 or +3 Scythe mastery in total?

Sorry for my nubbiness :<

+3

The bonus from the hood is stacking, which means it will add to any other modifier (rune). The non-stacking on the rune just means multiple runes will not add. So if you have a Minor Rune (+1) and a Major Rune (+2) you get +2 total, not +3. The hood would still add though, as it is stacking, which would give you the +3 total, not a +4.

Hood will add +1 to any rune set you use, but runes will not add to each other.

Don't be ashamed of yourself, and don't even call yourself a nub. You shouldn't forget that everyone was new to the game when they first started.

(non-stacking) do not stack with other (non-stacking), but (stacking) will stack with everything else.

So +1 (stacking)+2(non-stacking)+1(non-stacking)=3

You can try such things on heroes, since you can add and remove runes and insignia from their armors freely without losing nothing but salvaging kit uses.

you are a newb, no shame in that. stack and non stacking in GW indicate stacking with something of the same type.
I.E. scythe mastery runes do not stack, but Attunement runes do.