Hi

Assuming you have, or can make and save, the logo as a still image using either the jpg format or if you require a transparent background a png format file.

Add the still image to a lower empty track on the timeline, resize and position it using Effect, Movement effects, Size/position and then stretch the image or change the photo length - right click on the photo on timeline to get the pop up menu - for the full length of the movie.

If you wish to use a moving logo, it gets a little more complicated especially if you want a transparent background on it. 

Create the moving logo as a video for the duration of one cycle of movement, with a suitable coloured background.

Add to the timeline and adjust size position as above, add Chroma key effect for background transparency and then repeat the loop along the timeline for as many times as necessary for the full length of the movie.

HTH

John