Nostalrius Begins - Quality wow vanilla realm (1.12)

I am looking for a Disc Priest build for PVP. I am new to the Priest class so some guidance would be appreciated. How many points do I spend I Disc, Holy and Shadow? Specific's if possible on what abilities to spend my talent points? Thanks

bg healer - trispec:
https://en.nostalrius.org/talents/pries ... 2100510000

for damage: go shadow 18/0/33