Pre order at your LFGS.
Pre ordering helps them understand what to order and how much.
The sooner you pre order the sooner orders can be placed and hopefully avoid allocation.
My LFGS is getting a total of 4 of these in, and they are all going to people who have pre ordered.
Pre release works like any other TCG.
There are pre-release kits (Build and Battle boxes) which serve as the first time you can get your hands on the cards, sold at Organised Play locations usually in conjunction with a casual pre-release tournament.
The boxes have a 40 card pre-con, include 1...
Goodra is going to be an absolute Unit with Lake Acuity and Radiant Gardevoir.
And then it just heals itself.
Melony remains solid to accelerate Goodra, or an Arceus/Goodra deck would work insanely well too. Set up, and become the giant gooey road block.