For frame-accurate cutting of videos the individual video pictures can be displayed in the Preview Window. This is how it is done:
In the bottom right section of the program window click on tab 
Preview.
Grab the edge of a video object and drag it, following which the cutting location will be shown on the screen or in the preview window.
For fine adjustments you should stretch the timeline. See Expanding/compressing the time axis
The time indication and the timeline resolution can be matched with the frame rate of the videos to be edited in order to simplify video cuts. See Changing time display and timeline resolution.
See also Cutting objects