To see the style, trim and start options when you right click, make sure the YouTube video is not playing. i.e., it should be completely stopped (it should show thumb nail of the video should with a play button on it). Then you can right click on the thumbnail for the options to show up. The options menu does not show up until the video is stopped.
Alternatively, you can do the following, to access the options.
Style: Click on the video, go to 'Video Format' tab then click 'Video styles' for all the styles.
Trim: Trimming can only be done for the videos inserted from you PC (Offline videos). In your case, the video cannot be trimmed because the video is inserted directly from YouTube (Online video). That's the reason you cannot trim the video.
Start: Click on the video, go to 'Playback' tab, in 'Video Options' you can see 'Start', there you can access 'When clicked on' and 'automatically'.