Hi
"You mean like a screenshot?"
You don't create a screenshot....... 
"Or is snapshot somehow integrated in videopad?"
It is.......Under the right hand preview pane (version 3.12) there is a "camera" button. Clicking this creates a still image of the frame where the red cursor line is.
To get your still frame, step along the sequence by dragging the cursor until you have the last frame showing in the preview pane. (You can use the buttons mentioned below to pick out the last frame.) Nowt click the camera button. The snapshot will appear in your media list "image" file and, according to your default settings also on the desktop. Leave the cursor where it is and add the snapshot from your media list to the cursor position. Your sequence should now play and stop with the required still. The duration of any still image can either be set as a default value under the "Options" tab or you can drag out the ends of the still image directly on the sequence line to make it play longer, or you can switch into storyboard mode and alter the duration value that appears under the thumbnail frame .
As well as Borate's suggestion for setting a cursor position you can also step backwards and forwards a frame at a time by using the top set of < and > buttons either side of the "Play" button under the right hand preview pane. When doing this it is useful to zoom in a bit
Nat