1. By Table are you referring to the table control or a layout that you can place controls into? If it is the Table control you can drag and drop columns from the toolbox into the table. If you are referring to a Grid layout, add a region to the screen, set its Layout property to "Grid" and a new property for the number of columns will appear. Then drag your controls into the region
2. To use it in a repetition, you will need to make it a collection with a primary key. Repetition controls can only use collections or arrays as their initial value. You can then use your data component as your initial value of the repetition. When you place controls into the repetition, you can then use the repetition's value as your initial value for the nested controls
3. The button background color is determined by the theme of the device.