The end and start behavior of your clip can be changed in the Read node (pull downs near the frame range boxes). You can get it to freeze (default) loop or turn to black.
As has been pointed out the frame at which your footage is read in can also be changed. This is done in the frame box (empty by default) this will accept simple expressions (e.g. frame+30)
In addition the FrameHold node is really easy to use and understand.
I suspect that what is happening is that you have not changed the default of the in/out behavior. You are mistaking a frozen frame for no effect.