Under the Contents tab you can at the top select which layout you wish to use for the start page in question. There are 5 different layout options. They contain 1-6 sections in which you later add the different components.
You can select components for the sections from the Component gallery and then add Selected components. This is done using the buttons Add pos (1-6) -->, depending which layout you have decided to use.
At the bottom you can see who created/modified a start page and also when it took place.