How I can select multiple key frames in the timeline editor so that I can delete them all at once .
The timeline isn't actually an editor. It's simply a viewing port for all the keyframes in your animation. What you can do is:
- Go to the Graph editor and select the objects that are keyframed
- Move the playhead in the timeline to the keyframe you wish to delete
- Hover your cursor over the graph editor and press Ctrl-K
- Go to the next keyframe and repeat steps 2-3
- Press X to delete the selected keyframes
PLEASE NOTE This process works if you want to delete all keyframed information about the selected objects. If, say, you just want to delete X-Location info but not Y-Location info, you have to manually select each keyframe in the Graph Editor.
Hope this helps!