I've been playing pokemon for years and I still don't understand how stat

>>27128475
>priority based
what

>>27128475
They just multiply your stats by some value. For most stat increases, it's 3/2 for one stage, then 4/2, 5/2, etc until a max of 8/2 for six stages. For stat decreases, it's 2/3, 2/4, etc.until 2/8. Accuracy and Evasion are a little different where they only go up to 1/3 or x3 instead, but the same logic applies.

Lets say your att is 300, every boost gives you an aditional 50% of that 300.

1 boost 450
2 boosts 600
3 boosts 750
.
.
6 boosts(max) 1200