Designing is not easy and starting is hard! After giving a start to design a template, you probably need to some visual and content changes. Don't worry about (at least) your data sheet template if you're using TDSmaker. You can easily change template design and when you publish it, all data sheets created by changed template will be automatically updated.
OK, let's start with layout change. You can change your template layout easily from Page Settings/Layout section. Please watch the quick video below:
When you change the layout, the position of the elements on the page will be changed automatically. You can move them by cut-paste. Drag and drop function doesn't work between panels or columns.
Hint: You can change panel (column) size by using panel blue dotted line or while on any space of the panel without select any element, right click and open Panel Properties, then adjust margins of the panel (columns).