It's all in the help file available on the upper right and corner of the screen.
The scissors are visible on the bottom right hand corner of the preview screen, you just need to click on them.
"Chapter cutting: You have the possibility to cut off unwanted chapters or to split one movie in two parts. Click on the scissors to open the control element for cutting off unwanted chapters. Another bar appears below the play bar. The small points symbolize the chapters, the space shows the approximate length of each chapter. You can move the blue triangles to cut off unwanted chapters. Either you click on the orange bar to move the blue triangles step by step or you directly drag it to the chapter where you like to have it. The Play Slider above automatically moves to the position of the triangles so that you can watch the first movie scenes from each chapter. The green writing in the preview window shows you the chosen chapter and its play time. On the right hand side, in the title selection, you can see the chapter selection with each title
Splitting: If you want to copy the whole DVD or you want to copy a movie with extra length, it is advisable to split it over two DVD media. First of all you have to select â€œpreserve menusâ€ for keeping the overview. Via the â€œchapter cuttingâ€ function you can split the main movie in two parts while selecting for example the chapters 1-9 for the first DVD media. Select now further titles like â€œSpecial Featuresâ€ and start the copying process for the first DVD media. When the copying process has finished, please click on the â€œBackâ€ button until you reach the window with the title selection. Please click with the right mouse button into the title selection dialogue: You can invert your selection for the first DVD media, like in this example, it means that the chapters 10-16 of the main movie and the rest of the titles will be automatically selected
HINT: If you want to split a multi-angle movie, please cut off the same chapters for each camera angle. You can easily recognize titles with different camera angles, as they all have the same playing time!"