3.6 Stardust and Candy

In the process of catching pokémon you will accumulate stardust and candy. You gain 100 stardust from catching any pokémon. Stardust is used along with a small amount of candy to power up the CP (combat power) of your pokémon until it reaches max CP for your level and you cannot power it up any more. 

It is a good idea to save up stardust and only use it on pokémon that are nearly max CP already, or you will quickly exhaust your resources. After catching a pokémon, you also gain 3 candies of that same kind of pokémon. You can gain an additional candy by transferring the pokémon you caught back to the Professor. Warning: this will permanently lose that pokémon, so make sure you only transfer pokémon that you do not want to keep!

3.7 Evolving Pokémon

Pokemon Go Evolution

After you gain a certain amount of candy, you are able to evolve some pokémon into stronger forms. Evolving gives 500 experience, so it’s a good idea to evolve common pokémon like Pidgeys (who only take 12 candies to evolve) whenever possible.