Then, touch the cog at the top of the screen. You’ll see a section labeled Default within the Configure apps area.
There are four different types of apps for which you can set a default; home, browser, phone, and SMS. Touch SMS, for example, and you’ll see different choices. To change to one of these, select the new option.
You can make the exact change for the phone, browser, or home app, also known as a launcher. When you use one of these apps for the first time. It’ll ask if you want to make it the default. So if you change your mind, this is where you need to go to switch things around.