Hello Bazzao,
Welcome to this forum.
What did you mean about "default location where Lazarus stores projects"?
You can store your projects any where, without need to change any of the settings. If you changed the "Lazarus directory" you may have trouble because (if I'm not wrong) that is the Lazarus installation directory.
Maybe what you're looking for is the "Directory for building test projects".
I personally do not change any of the default settings, they work for me. If I want to start new project, I first will create a new folder on the location I like, then on Lazarus main menu > File > New > ... > and choose Save All and choose that folder I've just created.
Note:
If you run your new project without save it first (that "Save All" I mentioned recently), your newly created project will be saved on the "Directory for building test projects" mentioned earlier.