Power Stones

Aside from leveling up your Pokemon in the game, you can equip some power stones to generally boost its battle rating. In the game, there are 3 types of power stones. One that increases your Pokemon's HP, another one that increases a Pokemon's attack, and the rarest among them all, effect power stones. There are also some rare power stones that have additional passive boosts that increases critical attack rate, gives HP regeneration, and many more. Below is an example of how power stones are used and equipped to a Pokemon.

Rare Power Stones are different in color. The bronze ones usually have an additional buff, but usually not that great. Silver colored power stones tend to be better in comparison when it comes to the additional buffs. An expedition gauge is also present on the expedition map that gradually fills up when you successfully defeat the levels. When the gauge fills, the next expedition will automatically reward you with a special gold-colored power stone which are very rare and typically has the best boost effects.

Take note that HP power stones can only be slotted in slots that have the heart marker in it and Attack power stones on slots that have the fist marker. Not all Pokemon have the same configuration of power stone slots. Some are inclined to cater more HP power stones, and others Attack power stones. There are special slots too (from much rare Pokemon) that allows either HP or Attack power stones to be slotted in.

On the top most part of the Pokemon / power stone interface, you'll see slots beside your Pokemon's move set. This is where you typically equip effect power stones. Although hard to find, they usually grant you special effects like making your Pokemon's attack scattered, decrease the cool down of your special attack, and many more.

Linked slots like the example on the image below, grants you the ability to compound the effects of the effect power stones. For instance, if you link together 3 scatter-shot power stone in tandem with a beam type of move set, if your Pokemon normally has one beam, doing this configuration will give it 4 beams instead. Take note though that there usually is a consequence in using the scatter shot - decreasing the attack by 10%. This effect multiplies as you compound the power stones as well.

(on the image above, Hyperbeam attack skill is compounded to Scattershot and Wait Less stones)

Power stone slots are unlocked as you level up your Pokemon. There are instances where you can acquire a Pokemon that have (by default) more power stone slots unlocked from the get-go. Also, as you evolve a Pokemon, it usually will unlocked more power stone slots. Take note of the strengths of individual Pokemon and the particular move set that would benefit most when paired with the power stone slots it has.