To build your master version, the first thing you need to do is click into it. If your template is non-modular, then you will be able to see the whole email design. If you can already see your email design in the main window, then all you need to do is make the edits or changes you want to your master version. To do this, just click on the part of the email you want to change. The corresponding section of the editor will open up on the right hand side of the screen. Identify the part you want to change, e.g. image url, headline, copy, font colours etc. and then make your changes in the section on the right. Remember to press save when you are done.