Final cut faff

The timings of some of my clips are slightly off, therefore I had attempted to change the timings of my clips to fit the audio of the song. I have the original music video as the bottom layer when I am editing on final cut, I then place my footage on the layer above. This means I see my footage but I can hear the song playing so I know when each clip needs to start and stop.

So far this has proved effective, however some of my clips are either slightly too fast or too slow, but I could not find out how to edit the timings of clips. Right clicking on a clip shows the option change duration, however this doesn't seem to actually do anything at all. Another member of my media group had a similar problem, so we googled it and found out how to do it. 

Now that I know how to do it it's incredibly simple, you just need to select a clip then click the speedometer symbol. This opens a sub menu where you can change the percentage of the speed of the clip. 

One of my clips actually needed to be slow motion, so I just reduced the clip speed down to create this effect. I don't know whether there is a slow motion setting which can be applied to a clip, but the way I used worked just as well.