I'm starting a new campaign and have decided on a Monk. I know that chossing to be an Elf gives me a +2 Dex. For the Wood Elf subclass does that give you an additional +1 Wisdom or does that take the place of the +2 Dex? What I'm understanding so far is that creating a Wood Elf Monk would give me a +2 to Dex and a +1 to Wisdom.
You are correct
The subclass states that the bonus and other traits are in addition to the baseclass.
A Wood Elf gives you +2 Dex from the Elf base class and +1 Wis from the Wood Elf subclass and your Wood Elf Monk therefore starts with +2 Dex and +1 Wis.