Updating the SDK is as simple as installing it.

You can find the SDK located in the games directory.

An easy way to get to your game directory is to go onto Steam and right click on Wobbly Life and hit properties.

Then it is as simple as clicking on "Local Files" and then clicking on "Browse..." this will take you to the game directory.

You should see a folder called "ModTools".

Inside the ModTools folder there is two files. One for Audio modding (Wobbly Life Fmod Package.fspackage) One for Game modding (Wobbly Life Mod Tools.unitypackage)

You should be able to double click on the Wobbly Life Mod Tools.unitypackage otherwise drag that into your open Unity project.

Then all you need to do hit hit "Import" on the bottom right. This will install all the bits you need to make a basic mod.

That's all you need to do to update the SDK