Is there a way to apply a transition to all scenes on my time line ? I know I can add them one by one, but want to save some time
Activate the timeline, press CRTL+A to select all clips, then go to Sequence / Apply Default Transitions to Selection.
Just set your default transition to the one you want and be aware of sufficient handles.
If you just want transitions between the video, select all the video part by selecting/lassoing and holding down ALT, then hit Apply Default Transition To Selection.
Same goes for just the audio part.
When using Ctrl+A everything in the timeline video and audio transitions will be added.
You can also start the project with Automate to Sequence which will give you transitions straight away.
Thanks for your replies, that worked perfectly