Have a search on the forum and you will see everyone has asked this question at some point :)
The answer is there is no default preset, or way to load a default preset. What you need to do is save/export the preset in the state you want it to be in when the user first opens it. So load a preset, save, export, and that is the preset that the user should get when they first load, although it's not always as simple as that.